Systems and methods for interference detection in shared spectrum channels

ABSTRACT

A communication system, includes a satellite receiver in operable communication with a central server, a cellular node configured to operate within a proximity of the satellite receiver, and at least one mobile communication device configured to communicate (i) with the cellular node, (ii) within the proximity of the satellite receiver, and (iii) using a transmission signal capable of causing interference to the satellite receiver. The satellite receiver is configured to detect a repeating portion of the transmission signal and determine a potential for interference from the at least one mobile communication device based on the detected repeating portion.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. application Ser. No.16/142,933, filed Sep. 26, 2018, which prior application is acontinuation in part of U.S. application Ser. No. 15/809,658, filed Nov.10, 2017, now U.S. Pat. No. 10,116,381, which claims the benefit of andpriority to U.S. Provisional Patent Application Ser. No. 62/420,124,filed Nov. 10, 2016. U.S. Application Ser. No. 16/142,933 further claimsthe benefit of and priority to U.S. Provisional Patent Application Ser.No. 62/563,185, filed Sep. 26, 2017, U.S. Provisional Patent ApplicationSer. No. 62/564,115, filed Sep. 27, 2017, U.S. Provisional PatentApplication Ser. No. 62/609,071, filed Dec. 21, 2017, U.S. ProvisionalPatent Application Ser. No. 62/617,882, filed Jan. 16, 2018, U.S.Provisional Patent Application Ser. No. 62/621,354, filed Jan. 24, 2018,U.S. Provisional Patent Application Ser. No. 62/621,673, filed Jan. 25,2018, U.S. Provisional Patent Application Ser. No. 62/623,923, filedJan. 30, 2018, and U.S. Provisional Patent Application Ser. No.62/682,306, filed Jun. 8, 2018. The present application further claimsthe benefit of and priority to U.S. Provisional Patent Application Ser.No. 62/585,644, filed Nov. 14, 2017. The disclosures of all of theseapplications are incorporated herein by reference in their entireties.

BACKGROUND

The field of the disclosure relates generally to satellite servicetransmission systems, and particularly to management of fixed satelliteservice protection using real-time measurements.

Conventional fixed satellite service (FSS) earth stations, or sites,operate across a variety of spectrum bands for Geostationary Earth Orbit(GEO) satellites. The citizens band radio service (CBRS), defined by theFCC for fixed wireless and mobile communications operates in the3550-3700 MHz (3.55-3.7 GHz) band and use of this spectrum is authorizedand managed by a Spectrum Access System (SAS). The function of the SASis to maintain a database of all transmitters that use the CBRS band,including the transmitter locations and transmitter powers. The SAS usesa propagation model to determine interference between each FSS site andradio access points (AP) to ensure globally across the totality of itsmanagement area that the interference is below an acceptableinterference threshold at each location. The SAS uses frequency planningalgorithms known in the field of cellular communications for FrequencyDivision Multiple Access (FDMA), such as GSM. Thus, the SAS is able toallocate to each AP or citizens broadband radio service device (CBSD),the frequency of operation, bandwidth, and transmitter power.

The C-band, which is designated by the IEEE and used for satellitecommunications, covers the 3-8 GHz band. The FSS incumbents in the3.7-4.2 GHz of downlink C-band are identical in nature and technology tothe FSS incumbents within the 3.55-3.7 GHz CBRS band, and theseincumbents are provided co-channel and adjacent-channel protection (outof band) under the Part 96 rules of the United States FederalCommunications Commission (FCC). FSS incumbents within the CBRS band use3.665 to 3.7 GHz. Additionally, there is a requirement to limit theamount of aggregate interference across the entire downlink band toavoid gain compression at the Low Noise Amplifier (LNA) used forsatellite signal reception. The CBRS band is considered fairlymanageable at present due to the relatively small number of FSS sites(<100). In contrast, the 3.7-4.2 GHz band presently includes over 4700registered FSS sites, and may include as many or more unregistered FSSsites.

There are approximately, at this time, 160 geostationary satellitesutilizing the C-band for downlink in the 3.7-4.2 MHz spectrum. Eachsatellite typically employs 24 transponders, each with a 36 MHz signalbandwidth. Carrier spacing is 40 MHz, 2×500 MHz used on each satellite,and 12 carriers each for horizontal and vertical polarization. Thecarrier-to-noise (C/N) margins are typically 2-4 dB. The earth stationstypically employ multiple satellite dishes and frequency agile receiversto decode specific video/data streams off individual transponders. Theactual received bandwidth at the FSS sites varies. Multiple dishantennas are often used to obtain programming from multiple satellites.The United States C-band frequency chart is shown below (in GHz) inTable 1.

TABLE 1 (Frequencies in GHz) Horizontal Horizontal Vertical VerticalUplink Downlink Channel Downlink Uplink 3.720 1 5.945 5.965 2 3.7403.760 3 5.985 6.005 4 3.780 3.800 5 6.025 6.045 6 3.820 3.840 7 6.0656.085 8 3.860 3.880 9 6.105 6.125 10 3.900 3.920 11 6.145 6.165 12 3.9403.960 13 6.185 6.205 14 3.980 4.000 15 6.225 6.245 16 4.020 4.040 176.265 6.285 18 4.060 4.080 19 6.305 6.325 20 4.100 4.120 21 6.345 6.36522 4.140 4.160 23 6.385 6.405 24 4.180

The C-band downlink spectrum includes 500 MHz adjacent to the CBRS band,but sharing this adjacent spectrum with mobile and fixed wireless usagehas been problematic for technological reasons, and according to theexisting protection rules, which are highly conservative in nature.Satellite receivers, for example, are extremely sensitive, having aninterference threshold of −129 dBm/MHz according to the requirement fromFCC Part 96, and operate below the thermal noise level of the actualband itself, often working with effective thermal noise of 80K, withhigh gain antennas (satellite dishes) to amplify a weak satellite signalbefore detection. Relatively small power transmitters sharing the sameband may cause interference over distances of tens of kilometers orgreater.

There is no system currently in place to monitor and report operatingparameters, such as the actual frequency channel usage or the directionand elevation of reception of the satellite dish with its dish size(which determines its gain for satellite reception) at each FSS site.Accordingly, the protection rules are conservative because existing SASschemes have no capability to remedy FSS interference. Furthermore, noconventional propagation models accurately predict the transmission lossbetween the transmitter and the receiver, or to the FSS site from thepoint of interference, which further encourages over protection of FSSsites from wireless transmitters that occupy the same band.Additionally, building construction/demolition, as well atmosphericeffects, including change from one season to another, can causeunpredictable propagation behavior, and FSS site operators mayfrequently change the FSS site operating parameters, which encouragesthe operators to register their respective FSS sites for full arc andfull bandwidth protection when, in practice, the actual use may be muchmore restricted.

FIG. 1 is a schematic illustration of a conventional satellite serviceprotection scheme 100 for an FSS site 102. FSS site 102 includes atleast one earth satellite ground station 104, or earth station 104,which generally includes a dish and a frequency agile receiver (notseparately numbered), for receiving and decoding video/data streams fromsatellite 106 (e.g., GEO C-band satellite). Protection scheme 100further includes a CBSD 108, which may be a base station in the cellularcontext, such as an eNodeB for LTE, mounted on a vertical support ortower 110. CBSD 108 may be a radio access point (AP) used for fixedwireless access. Authorization and resource allocation of CBSD 108 isgoverned by an SAS 112, which is in operable communication with CBSD 108over a data link 114 (e.g., wireless or wired Internet connection,etc.).

In operation of protection scheme 100, CBSD 108 requests authorizationand resource allocation from SAS 112. SAS 112 has knowledge of theoperating parameters of FSS site 102, which are communicated over areporting link 115. Initially, the resource allocation to CBSD 108 canbe provided using a propagation model to avoid interference. Thisinterference modeling can model co-channel, adjacent channel, secondadjacent channel, and aggregate band interference. In this example, SAS112 may use a frequency planning algorithm that is similar to a modelused for cellular networks to determine the allocation of both thechannel frequency and power. However, this modeling technique is notaware of the actual loss between CBSD 108 and FSS site 102, which mayinfluenced by obstructions 116 (buildings, elevated ground, seasonaleffects, foliage, etc.) along an actual transmission path 118therebetween. SAS 112 therefore implements protection scheme 100according to an estimate model that utilizes a mapped distance 120between CBSD 108 and FSS site 102 to predict a pass loss estimate.

However, because SAS 112 cannot measure the actual loss along the actualtransmission path 118, the path loss estimate will be inaccurate, andtypically based on the worst-case scenario. Such inaccuracies thereforegenerally encourage over protection of the FSS sites and results inlimited CBRS spectrum utilization, as well as the C-band downlinkspectrum overall. Accordingly, it would be desirable to develop an FSSprotection scheme that can determine actual path loss considerations inreal time to maximize use of available spectra, but without impairingthe protection to the sensitive satellite receivers.

FIG. 2 is a schematic illustration of a conventional satellite serviceprotection system 200 implementing protection scheme 100, FIG. 1, forearth station 104 receiving a video/data stream 202 from satellite 106.In this example, stream 202 has a total transmit spectrum of 500 MHzbetween 3700 MHz and 4200 MHz, that is, 500 MHz of the GEO C-bandsatellite downlink spectrum adjacent to the CBRS band. Under the currentgovernment rules, protection scheme 100 implements the FCC Part 96protection scheme for 3600-3700 MHz earth stations. System 200 includesa low-noise block (LNB) 204 and a headend 206. LNB 204 includes, forexample, a feed horn 208, a bandpass filter 210, and anLNA/downconverter 212. An FCC reference point (not shown), forinterference calculations by the SAS, is generally taken betweenbandpass filter 210 and LNA 212. Headend 206 includes a plurality ofchannel receivers 214.

In operation of system 200, LNB 204 functions as the receiving devicefor the dish of earth station 104, collecting from the dish theamplified received radio waves as a block of frequency sub-blocks athrough l (e.g., 12×40 MHz channels, see Table 1, above). LNB 204amplifies and downconverts the collected block into a lower block ofintermediate frequencies (IF) (e.g., 950-1450 MHz), which are thendistributed as individual sub-blocks (c, f, b, i in this example) alonga receiver signal distribution chain 216 to respective channel receivers214, which are typically contained in a distribution rack in headend206.

In this example, earth station 104 utilizes a 2-meter antenna, withprotection of FSS LNB from gain compression of −60 dBm aggregate LNBinput signal level from all terrestrial radio emissions within 40 kmradius of the FSS across the 500 MHz band. Protection of FSS receivernoise floor is −129 dBm/MHz, as discussed above, from all co-channelterrestrial radio signals within 150 km radius of the FSS, based onmaximum noise equal to −10 dB I/N, for 0.25 dB max noise rise atmeasurement point. It should be noted, that since many FSS sites use the3.7-4.2 GHz band across the United States, such protection areas of 40km and 150 km radius frequently overlap each other, and thus theprotection criteria to address interference for each radio access pointsharing this band must be satisfied at each FSS site within thevicinity.

FCC rules also specify the acceptable levels of adjacent channelinterference in the first and second adjacent channels, e.g., whichallow 40 and 52 dB higher signal strengths, respectively, for the firstand second adjacent channels due to their increased frequency separationfrom the central channel, to that used for signal reception.Accordingly, the re-use of unused channels is optimally based initiallyupon the second adjacent channel before the first adjacent channel in anoptimization strategy for optimum interference management. The FCC Rulesalso specify standard FSS dish gain profile (H and V planes) and alsoband pass filter attenuation. The antenna pattern (not shown) outputfrom the dish is highly directional, the Half Power Beamwidth (HPBW) isapproximately 1.3 degrees, and the antenna gain is 36.5 dBI for a 2 mdiameter dish with an efficiency of 65%.

Conventionally, not all of the twelve 40 MHz channels (a through l) overone polarization (see Table 1, above) are actually demodulated alongdistribution chain 216 for a given FSS site (e.g., FSS site 102, FIG. 1,having 1-N earth stations 104). In the example illustrated in FIG. 2,only a third of the twelve polarization channels (that is, 24 channelsin total, but only twelve for each of the two polarizations), aredemodulated at headend 206, with protection scheme 100 requiringco-channel protection of an “unused” portion 218 of the transmitspectrum unavailable for use by other CBSDs 220 (or Radio Access Points(RAPs)) seeking authorization and resource allocation from SAS 112 forFSS site 102. That is, in this example, unused portion 218 represents320 MHz of available terrestrial spectrum that is wasted and unusableunder protection scheme 100. Additionally, in consideration of other FSSsites in the vicinity of a particular CBSD/RAP 220 that may utilizedifferent satellite down-link channels, there will be furtherconstraints on the spectrum availability. In areas of high FSS sitedensity, the whole of the 500 MHz of spectrum will become unavailable tothe particular RAP.

FIGS. 3A-3B illustrate data tables 300, 302 for loss and separationdistances according to the conventional protection scheme 100, FIG. 1,and system 200, FIG. 2. Tables 300 and 302 are each illustrated withrespect to co-channel, LNB blocking, first adjacent out-of-band emission(OOBE) and second adjacent OOBE for a single interfering transmitter. Inconsideration of the loss values taken from table 300, minimumseparation distances to reduce interference below the various thresholdsin table 302 are determined using a free space path loss (FSL) equationand two common propagations models used for cellular communications:Cost 231 Hata (231 Hata), Cost 231 Walfish-Ikegami (231 WI). Thesetables illustrate the significant variations in associated protectiondistances depending on the model choice. For example, for an Azimuth of0 degrees, a satellite dish elevation of 5 degrees and a satellite gainof 14.5 dB, the predicted separation distance is 6940 km for FSL, 7.4 kmfor 231 WI and 3.4 km for 231 Hata.

Use of the most conservative model, FSL, will result in massive overprotection of the FSS and under-utilization of the spectrum. In theexample illustrated, the dish size is 2 m, antenna height of FSS is 4 m,and small cell height is 1.5 m for both 231 WI and 231 Hata. As can beseen from these examples, the FSL calculation is not able to take intoaccount actual terrain/obstacle considerations; the FSL calculation doesuse assumptions on antenna height. Even the use of other models such as231 Hata and 231 WL require the choice of parameters that reflectdifferent terrains profiles and even these can produce significantvariations within themselves based on that choice. Furthermore, becausesuch empirical models only produce a prediction of the average lossbetween two points in space, in practice, the actual loss between thesetwo points may significantly depend on many other factors including theterrain therebetween.

BRIEF SUMMARY

In an aspect, a system is provided for protecting a fixed satelliteservice site. The system includes at least one earth station, a firstbeacon detector disposed within close proximity to the at least oneearth station, a central server in operable communication with the fixedsatellite service site and the first beacon detector, an access pointconfigured to request authorization from the central server for resourceallocation, and a beacon transmitter disposed within close proximity tothe access point. The beacon transmitter is configured to transmit abeacon signal to one or more of the central server and the first beacondetector, and the beacon signal uniquely identifies the access point.

In an aspect, a communication system includes an earth stationconfigured to receive a downlink transmission from a satellite andtransmit an uplink transmission to the satellite. The communicationsystem further includes a server in operable communication with theearth station, a beacon detector in operable communication with theserver, an access point configured to operate within a proximity of theearth station, and a beacon transmitter disposed within close proximityto the access point. The beacon transmitter is configured to transmit abeacon signal to one or more of the server and the beacon detector. Thebeacon signal uniquely identifies the access point. The server isconfigured to implement a measurement-based protection scheme withrespect to at least one of the downlink transmission and the uplinktransmission.

In an aspect, a communication system, includes a satellite receiver inoperable communication with a central server, a cellular node configuredto operate within a proximity of the satellite receiver, and at leastone mobile communication device configured to communicate (i) with thecellular node, (ii) within the proximity of the satellite receiver, and(iii) using a transmission signal capable of causing interference to thesatellite receiver. The satellite receiver is configured to detect arepeating portion of the transmission signal and determine a potentialfor interference from the at least one mobile communication device basedon the detected repeating portion.

In an aspect, a method is provided for detecting interference to asatellite receiver from a mobile communications device in communicationwith a cellular node in proximity to the satellite receiver. The methodincludes steps of powering the cellular node, causing the cellular nodeto broadcast a primary synchronization signal (PSS) at a nominal powerlevel, capturing the broadcast PSS, determining, from the captured PSS,an operation of the cellular node, and instructing the cellular node,based on the determined operation, to (i) operate at full power, (ii)operate at a lower power, or (iii) cease operation.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentdisclosure will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 is a schematic illustration of a conventional satellite serviceprotection scheme according to an estimate model.

FIG. 2 is a schematic illustration of a conventional satellite serviceprotection system implementing the scheme depicted in FIG. 1.

FIGS. 3A-3B illustrate data tables for gain and separation distancesaccording to the conventional protection scheme depicted in FIG. 1 andsystem depicted in FIG. 2.

FIG. 4 is a schematic illustration of a satellite service protectionscheme, according to an embodiment.

FIG. 5 is a schematic illustration of a satellite service protectionsystem implementing the scheme depicted in FIG. 4, according to anembodiment.

FIG. 6 is a flow diagram for an exemplary process for operating thesatellite service protection system depicted in FIG. 5, according to anembodiment.

FIG. 7 is a graphical illustration depicting a comparison ofconventional fixed point-to-point distributions for the 4 GHz band andthe Lower 6 GHz band.

FIG. 8A is a graphical illustration depicting a conventional earthstation location distribution for the 4 GHz downlink band.

FIG. 8B is a graphical illustration depicting a conventional plotcomparison of fixed microwave earth station distribution trends for the6 GHz uplink band and the 4 GHz downlink band.

FIG. 9 is a graphical illustration of a chart depicting relativepercentages of existing earth station database problems conventionallyencountered.

FIG. 10 is a schematic illustration of a shared use system, according toan embodiment.

FIG. 11A depicts an exemplary protection zone layering scheme, accordingto an embodiment.

FIG. 11B illustrates a data table for calculating respective parametersof area zones according to protection zone layering scheme depicted inFIG. 11A.

FIG. 12 is a schematic illustrations of a shared use system within theexclusion zone depicted in FIG. 11A, according to an embodiment.

FIG. 12A illustrates a multi-zone operational distribution of UEs aroundthe FSS site depicted in FIG. 11A, according to an embodiment.

FIG. 12B is an overhead view of a partial schematic illustration of acorner effect, according to an embodiment.

FIG. 12C is a partial schematic illustration of a hotspot effect,according to an embodiment.

FIG. 13 is a schematic illustration of a shared use system thatimplements a measurement-based protection scheme for a self-calibratingpropagation model, according to an embodiment.

FIG. 14 is a graphical illustration depicting comparative data plots ofsingle-slope and dual-slope models for high density commercialmorphology-per-clutter classifications, according to an embodiment.

FIG. 15 is a graphical illustration depicting a plot of an addressablepopulation with respect to a radius of an exclusion zone, according toan embodiment.

FIGS. 16A-16B illustrate data tables for satellite protection maximumpath loss with respect to a single access point, and 800 access points,respectively, within the satellite beam width, according to anembodiment.

FIG. 17 illustrates a patterned grid region including a plurality ofcontiguous grid blocks, according to an embodiment.

FIG. 18 is a graphical illustration depicting comparative data plots1802 of dual-slope propagation models, according to an embodiment.

FIG. 19 is a schematic illustration of a fixed satellite service siteconfigured to implement the protection scheme depicted in FIG. 4,according to an embodiment.

FIG. 20 is a schematic illustration of a beacon detection systemimplementing the earth station and the platform-mounted beacon receiverdepicted in FIG. 19, according to an embodiment.

FIG. 21 is a schematic illustration of a beacon detection systemimplementing the earth station and the integrated beacon receiverdepicted in FIG. 19, according to an embodiment.

FIG. 22 is a schematic illustration of a distributed antenna systemconfigured to implement the protection scheme depicted in FIG. 4,according to an embodiment.

FIG. 23 is a schematic illustration of a multiple-antenna shared-usesystem, according to an embodiment.

FIG. 24 illustrates a far field beam pattern for a multiple antennasystem, according to an embodiment.

FIG. 25 is a schematic illustration of a multiple antenna system,according to an embodiment.

FIG. 26 is a schematic illustration of a multiple antenna system,according to an embodiment.

FIG. 27 is a schematic illustration of a multiple antenna system,according to an embodiment.

FIG. 28 is a schematic illustration of a multiple antenna system,according to an embodiment.

FIG. 29 is a schematic illustration of multiple antenna system,according to an embodiment.

FIG. 30 is a schematic illustration of a multiple antenna system,according to an embodiment.

FIG. 31 is a schematic illustration of a mobile network implementingjoint beamforming and null forming, according to an embodiment.

FIGS. 32A-C are schematic illustrations of a mobile network configuredto implement dynamic null forming for different respective frequencies,according to an embodiment.

FIG. 33 is a schematic illustration of a mobile network implementingchannel estimation, according to an embodiment.

FIG. 34 is a schematic illustration of a mobile network implementingsatellite system information relay, according to an embodiment.

FIG. 35 is a flow diagram of an exemplary process for operating amultiple antenna system, according to an embodiment.

FIG. 36 is a schematic illustration of a multiple antenna systemimplementing a directional antenna subsystem for satellite downlinkprotection, according to an embodiment.

FIG. 37A is a schematic illustration of a mobile network implementingdirectional coverage implementing the directional antenna depicted inFIG. 36.

FIG. 37B is a schematic illustration of a mobile network implementing aconventional omni-directional antenna.

FIG. 38 is a schematic illustration of a communication system, accordingto an embodiment.

FIG. 39 illustrates an exemplary interference detection system,according to an embodiment.

FIG. 40 is a schematic illustration of a signal frame architecture,according to an embodiment.

FIG. 41 is a schematic illustration of a signal frame architecture,according to an embodiment.

FIG. 42 is a flow diagram for an exemplary interference detectionprocess, according to an embodiment.

Unless otherwise indicated, the drawings provided herein are meant toillustrate features of embodiments of this disclosure. These featuresare believed to be applicable in a wide variety of systems including oneor more embodiments of this disclosure. As such, the drawings are notmeant to include all conventional features known by those of ordinaryskill in the art to be required for the practice of the embodimentsdisclosed herein.

DETAILED DESCRIPTION

In the following specification and claims, reference will be made to anumber of terms, which shall be defined to have the following meanings.

The singular forms “a,” “an,” and “the” include plural references unlessthe context clearly dictates otherwise.

“Optional” or “optionally” means that the subsequently described eventor circumstance may or may not occur, and that the description includesinstances where the event occurs and instances where it does not.

As used herein, the term “database” may refer to either a body of data,a relational database management system (RDBMS), or to both, and mayinclude a collection of data including hierarchical databases,relational databases, flat file databases, object-relational databases,object oriented databases, and/or another structured collection ofrecords or data that is stored in a computer system.

Furthermore, as used herein, the term “real-time” refers to at least oneof the time of occurrence of the associated events, the time ofmeasurement and collection of predetermined data, the time for acomputing device (e.g., a processor) to process the data, and the timeof a system response to the events and the environment. In theembodiments described herein, these activities and events occursubstantially instantaneously.

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about,” “approximately,” and “substantially,” are notto be limited to the precise value specified. In at least someinstances, the approximating language may correspond to the precision ofan instrument for measuring the value. Here and throughout thespecification and claims, range limitations may be combined and/orinterchanged; such ranges are identified and include all the sub-rangescontained therein unless context or language indicates otherwise.

The embodiments described herein provide systems and methods thatintroduce transmitter beacons and beacon detectors into an SAS orcentral server system to create a closed loop system that produces nosignificant interference to sensitive satellite receivers. The presentembodiments implement actual real-time measurements, that is, ameasurement-based protection (MBP) system, where each transmitter beaconis assigned its own unique identifier (ID) such that beacon detectorsmay be used to build an accurate and up-to-date propagation map ormodel. The MBP systems described herein further serve a dual purpose ofallowing a central server to remedy the system in the event of asystematic change or actual interference experienced. In such cases, theMBP system utilizes the beacon transmitters and detectors to trace backto the source of the interference, and then affect system changes toprotect particular FSS sites from the encountered interference.

In some embodiments, the techniques of the MBP system are extended toimprove or calibrate to the propagation model that may be used toinitially assign resources to a new access point (AP). The MBP systemmay, in such circumstances, implement the techniques such that thebeacon transmitters transmit periodically to be received by one or morebeacon detectors within the transmission proximity. Such a managementsystem is thus a dynamically adaptable to changes in the environment ofthe transmission path. For example, the MBP system would know, inreal-time, the effect on the path loss from a sufficiently tall buildingbeing built (or removed) between the beacon transmitter and detector,and use this real-time measurement to more accurately utilize thetransmission spectrum then can be done under the conventional approachthat only performs estimate calculations based on maps. Furthermore, theMBP system is capable of adapting to seasonal changes between spring andfall to take into account the differences in propagation through trees,which is a major limitation of conventional propagation tools.

More specifically, the present MBP system improves over conventionalCBSD to CBSD protection, e.g., in the priority access license (PAL) andgeneral authorized access license (GAA) sub-bands, by using the actualpath loss measurements from the CBSD, instead of relying on propagationmodels, which are imprecise in the CBRS band 3.55-3.7 GHz, as well asother frequencies, generally due to clutter effects and buildingpenetration loss as well as real time changes to the environment.

Because the MBP system of the present embodiments is implemented as aclosed loop, and thus creates effectively zero interference (i.e.,interference which has no meaningful effect on the satellite receptionitself), the system is not limited to only CBSDs, but may also beapplied with respect to APs and user equipment (UE/UEs) for mobile usageand small cell configurations. In an exemplary embodiment, individualbeacon transmitters are configured to operate below the satellite noisefloor, thereby allowing for significant link budget extension through awide deployment of beacon transmitters and detectors.

Accordingly, the present systems and methods acknowledge the appropriatepurpose of the incumbent protection requirements of Part 96, and proposean alternative solution that implements an MBP scheme that achieves thesame protection goals for FSS sites, but without over-protecting the FSSsites. The present MBP schemes may assume that all of the 575-600 MHzC-band downlink (i.e., between 3.6-4.2 GHz) FSS bandwidth is co-channelto CBRS/RAP at every earth station site, or alternatively may, in anintelligent fashion, be further configured to consider co-channel,adjacent channel, second adjacent channel and aggregate interferencelimits to optimally use the spectrum. The conventional use of theconservative path loss predictions, while achieving the statedprotection goals, unfortunately locks out CBRS/RAP usage by largegeographic areas and results in inefficient use of the spectrum. Incomparison, the present MBP schemes achieve the same protection goals,but also allow for control of spectrum reuse in a deterministic andnon-interfering manner maximizing the spectrum utility. The present MBPsystems and techniques further provide FSS receiver bandwidth usagereporting to a central server database (e.g., such as the SAS), whichenables the central server to enforce FCC requirements withoutover-protecting (i.e., locking out usable spectrum). Additionally, theMBP embodiments presented herein have more general applications acrossother bands and systems, and will result in a dramatic improvement ofspectrum efficiency throughout.

The present MBP system and methods herein thus implement an empiricalmeasurement scheme that improves over conventional CBSD-to-CBSD, orRAP-to-RAP, protection schemes and resource assignment calculations,which results in increased spectral efficiency, while more effectivelymanaging potential interference to the FSS site from individual mobiletransmitters or radio access points and devices (e.g., UEs) associatedwith respective APs. Through these innovative and advantageoustechniques, the central server is further able to remedy a situationwhere interference may be encountered, for example, by instructing aneNodeB or AP to change its frequency channel, and through these changes,associated connected devices as well, to avoid interference.

Additionally, if the noise floor of the FSS has increased and isapproaching an unacceptable threshold, due to the effect of theaggregation of individual mobile transmitters or radio access points anddevices, the central server is able to instruct the devices in thevicinity of the FSS to reduce their transmitter power by smallincrements to bring the FSS noise floor to that of the originalacceptable limit. The improved model derived by the present MBP systemthus advantageously achieves this solution in an accurate manner, andwith a minimum reduction(s) to the respective transmitter powers, andwithout a significant reduction in the range and coverage. Theseremedying techniques may therefore be extended to microcells that sharethe same spectrum. According to the present system and methods, new RAPsmay be introduced within the vicinity of sites that are considered toalready include a significant number of RAPs within a 40 km radius ofthe FSS.

The present embodiments are further advantageously applicable tooperation within other frequency bands, including extensions to 5G,where radio spectrum sharing could be controlled and/or managed by acentral server using various sharing strategies to allow multiple radiotransceivers to coexist with each other and other non-controlledservices (FSS in this example) that receive noise floor protection andfront end blocking protection. These techniques are described morespecifically below with respect to the following drawings.

FIG. 4 is a schematic illustration of a satellite service protectionscheme 400. In an exemplary embodiment, scheme 400 includes an FSS site402 including at least one earth station 404, having a dish and afrequency agile receiver (not numbered), for receiving and decodingvideo/data streams from a satellite 406 (e.g., GEO C-band satellite).Scheme 400 further includes at least one AP 408. AP 408 may include,without limitation one or more of a wireless AP, an eNodeB, a basestation, a CBSD, or a transceiver. In the exemplary embodiment, AP 408is mounted on a first support 410. However, many APs are withinbuildings. The MBP capabilities of scheme 400 though, would take intoaccount the penetrations loss of walls and metalized windows.

Authorization and resource allocation of FSS site 402 is governed by acentral server 412. In some embodiments, central server 412 includes anSAS, and is in operable communication with AP 408 over an AP data link414. Additionally, an FSS reporting link 415 communicates the operatingparameters of FSS site 402, including without limitation, coordinate,elevation, azimuth angle, elevation angle, receiving channel(s),satellite arc(s), frequency range, receiving channels, antenna model,antenna height, antenna gain, feed horn model(s), LNB model(s), servicedesignator(s), operation status of the FSS earth station.

Scheme 400 also includes at least one beacon transmitter 416 and atleast one beacon detector 418. In the exemplary embodiment, beacontransmitter 416 is disposed in close proximity to AP 408, such as onfirst support 410, or alternatively as an integral component or functionof AP 408. Similarly, beacon detector 418 is disposed within FSS site402, in close proximity to earth station 404, and may be structurallymounted on the dish/antenna thereof, or alternatively on an independentsecond support 420, or alternatively as an integral component of FSSsite 402. In some embodiments, each AP 408 includes at least one beacontransmitter 416, and each earth FSS site includes at least one beacondetector 418. In the exemplary embodiment, beacon transmitter 416includes at least one transmitter, or alternatively, at least onetransmitter and at least one receiver (not shown). Beacon detector 418includes at least one receiving portion. In some embodiments, beacontransmitter 416 and beacon detector 418 includes transceivers.

Beacon transmitter 416 is in operable communication with central server412 over a beacon data link 422, and beacon detector 418 is in operablecommunication with central server 412 over a beacon measurementreporting link 424. In an embodiment, beacon detector 418 is locatedoutdoors, using a dedicated antenna (not separately shown). In anotherembodiment, beacon detector 418 is inserted in the post-LNB signal chain(described further below with respect to FIG. 5). In some embodiments,beacon detector 418 may be located outdoors and attached to the station404. Beacon detector 418 may separately communicate directly withcentral server 412.

Beacon detector 418 is configured to receive a direct beacon signal 426from beacon transmitter 416. Beacon detector 418 may be integratedwithin the system of FSS site 402 or implemented as a standalone system.In the exemplary embodiment, direct beacon signal 426 constitutes anin-band beacon RF signal including a unique ID, and is transmitted at apower that would not by itself cause any meaningful interference to FSSsite 402. Beacon signal 426 may be transmitted on either an on-demand ora periodic basis. In other embodiments, the beacon can transmit theunique ID, its location, and its transmitter power, but is not limitedto these parameters. In the exemplary embodiment, the location,frequency of operation, transmitter power, etc. are communicated by overdata link 422 to maximize the range of detection. Beacon transmitter 416is further configured to have its own unique ID that can be registeredwith a database (not shown in FIG. 4) of central server 412.Accordingly, in the case where AP 408 is a source of potentialinterference, central server 412 is capable of not only foreseeing ordetecting the interference, but also of associating the foreseen ordetected interference with the potential interference source (AP 408 inthis example) through the unique ID. Moreover, by being able to identifythe source of potential interference, central server 412 may be furtherconfigured to remedy the foreseen or encountered interference by, forexample, instructing the interfering device to change its transmissionchannel and/or lower its transmission power or cease operation.

According to the exemplary embodiment illustrated in FIG. 4, the in-bandbeacon transmission from beacon transmitter 416 allows measurement bycentral server 412 of the actual path loss between AP 408 and FSS site402. In an embodiment, beacon detector 418 is further configured toinclude a means of measuring the signal of the interference andreporting the measured signal to central server 412 for calculation ofthe link loss. Furthermore, in contrast with FIG. 1, FIG. 4 does notillustrate obstructions, because the presence or absence of obstructionsbetween AP 408 and FSS site 402 is rendered irrelevant (for path lossdetermination purposes) by the nature of real-time measurements. ThisMBP scheme is advantageously applicable to interference calculationsperformed by central server 412.

In an exemplary embodiment, central server 412 further utilizes knownlocations (e.g., in the form of coordinates including longitude,latitude, and elevation) of both FSS site 402 and AP 408, as well as thetransmit power and antenna pointing angles, to calculate the specificprotection/protection scheme for FSS site 402 with respect to AP 408. Insome embodiments, the protection scheme implemented by central server412 further utilizes a path loss equation that utilizes empiricalmeasurement data from one or more beacon detectors 418 (i.e., uponvalidation of the equation by the FCC and/or other relevant governingbodies). Central server 412 effectively implements the FCC protectionrequirements and, according to the embodiments herein, such FCCprotection requirements may be advantageously changed, for example, ifthe protection criteria was deemed to be more or less conservative byitself.

In the exemplary embodiment, transmissions from beacon transmitter 416(i.e., over links 422, 426) include the unique ID of the transmitter, aswell as the transmit power of beacon transmitter 416 itself. Optionally,beacon transmitter 416 further transmits location information (e.g., GPSdata and/or map data), and/or one or more UEs associated with AP 408.Under this optional configuration, central server 412 may be furtherconfigured to manage not only potential interference from AP 408, butadditionally potential UE interference along with consideration of themeasured path loss. In an embodiment, the actual path loss is determinedby central server 412 using an in-band measurement of a beacon receivedsignal strength indicator (RSSI), and/or in further consideration of thetransmitted effective isotropic radiated power (EIRP), as well as ameasured antenna gain at one or both of AP 408 and earth station 404.Central server 412 may then assign AP resources according to any and allof these measured parameters.

In further operation, a wide-scale deployment of beacon detectors 418 atexisting registered and unregistered FSS sites 402 (estimated at8,000-10,000 sites or more at present) will provide a significantquantity of real-time information about each transmitting AP 408, andtheir respective effects on individual earth stations 404. The amount ofinformation is considerable that can be collected from thousands ofbeacon detectors (each having, for example, a range of approximately 2-5km depending on the morphology), in a broad deployment at thousands ofFSS sites, which are much more highly concentrated in heavily populatedareas. The beacon-based MBP protection scheme of scheme 400 thusrealizes a two-fold advantage over conventional protection schemes: (1)individual beacon transmitters 416 may be configured to identifythemselves to other devices within range, thereby allowing other systemelements to carry out measurements and build propagation maps; and (2)in the event of a systematic change or an emerging problem, centralserver 412 may be configured to utilize the unique beacon IDs to traceback to the source of actual interference and implement remedialmeasures. In the exemplary embodiment, individual beacon transmitters416 transmit to other transceivers (e.g., beacon detectors 418, centralserver 412, other beacon transmitters 418 having a receiver component)within range, and feed the signal strength back to a centralizeddatabase (not shown in FIG. 4) of central server 412 (e.g., an SAS).

The MBP scheme of scheme 400 realizes still further advantages overconventional protection schemes that utilize path estimates based onlocational maps and propagation models. Conventional CBSDs and APs areknown to include GPS capability for an SAS to determine their respectivelocations on the map. Propagation models built by the conventional SAS,however, must make a number of numerical assumptions (e.g., effects frombuilding heights, number of windows, building materials, effects oftrees, contours of the path, general clutter, etc.) to calculate a pathloss estimate between the transmitter and the FSS site. According toscheme 400 though, which performs real-time measurements, thepropagation model may be dynamically built by central server 412 fromempirical data, and updated in a timely manner based on actual systemconditions.

In one exemplary operation, scheme 400 implements an MBP protectionscheme that initially utilizes the conventional estimated propagationmaps. That is, central server 412 may initially operate by performingcalculations using estimated propagation maps to determine appropriatefrequencies and power levels for individual APs 408. Over time though,as empirical data is collected from beacon transmitters 416 and beacondetectors 418. Such real-time measurements of power and operatingconditions may be fed back to central server 412 to update the initialcalculations in order to more accurately assign (and reassign) resourcesunder optimum conditions. Central server 412 is then able to becomeaware of potential interference in real-time, and take remedial measuresto resolve such problems, as described above.

In this example, beacon transmitters 416 will be in close proximity tothe channel on which transmission is sought, and centralized server 412may initially instruct AP 408 to operate at a particular frequency andpower level. However, before an individual AP broadcasts across theentire band, AP 408 may first cause a beacon transmitter 416, in closeproximity to the particular band, to transmit a beacon signal, which maybe within the band itself, or in an adjacent guard band. Thus, byinitiating transmission from beacon transmitter 416 prior to broadcastfrom AP 408, central server 412 is able to detect the beginning, learnthe properties of the associated AP 408, and determine whether operationof AP 408 would cause interference with respect to a particular FSS site402.

In the case where central server 412 determines that a particular AP 408will cause interference, central server 412 may be further configured toinstruct AP 408 to lower its power, operate on a different channel, orsimply deny authorization and hence operation. In at least one example,central server 412 may reevaluate the beacon power level and determinethat the level is sufficiently low enough to allow operation. Becausescheme 400 continually receives beacon signal information, if AP 408 isallowed to broadcast but nevertheless causes interference, centralserver 412 is capable of correcting such a situation in a timely manner.In some embodiments, the band gaps between channels may be utilized inthe MBP scheme of scheme 400. Because the transmitted signal of thebeacon itself does not cause interference to satellite reception, thebeacon signal and the transmitter IDs may be transmitted in any of thechannels (12 in this example) of the transmit spectrum. The ID of aparticular beacon transmitter 416 always stays the same, and thereforemultiple beacons can overlap with other beacons within the same range,and still be decodable by central server 412, even in the case where twodifferent beacons transmit within the same band gap.

According to the exemplary scheme 400, the transmitted beacon signalitself may constitute low spectrum noise density in the C-band, may bespread across the whole of the band, or may be a narrow-band signal(e.g., noise) of the order of about 10-1000 Hz. By itself, this spectrumdensity—even across the whole of the video channel—is not sufficientlyhigh to cause any interference. According to exemplary scheme 400, thebeacon is transmitted in a guard band. The beacon signal is though,sufficiently high that it may be actually measured, i.e., detected, bybeacon detectors 418 and the information fed back to central server 412.

Scheme 400 is therefore configured to operate in multiple stages. In aninitial stage, AP 408 requests authorization from central server 412,and central server calculates, by an initial propagation model or actualmeasurements, a safe frequency and power for AP 408 to transmit. In asecond stage, beacon transmitter 416 transmits a modulated signal tobeacon detector 418, which may be then used by central server 412 todetermine whether the amplitude will create interference. As discussedabove, when the beacon signal is transmitted within the channel itselfor in a guard band, there is no interference to satellite reception. Thebeacons' spectral power density may operate below the thermal noiselevel for the band itself. Furthermore, in the case where the beaconsignal is out of band, or within band gaps, scheme 400 would be evenmore tolerant of the beacon, and may increase the beacon transmit power,and thereby potentially the beacon range as well. In a third stage,central server 412 determines that there is no interference, and informsAP 408 of the available resources for the broadcast. In the case whereinitial stages are based on propagation model estimates, subsequentreal-time measurements by scheme 400 are utilized in later stages todynamically manage AP 408.

According to the advantageous system and protection scheme of scheme400, the highly conservative safety margins that are built into theconventional protection schemes may be avoided, because scheme 400 isable to remedy interference that is encountered within the conventionalsafety margins. Scheme 400 is capable of registering the beacons andcontrol the associated AP transmission through the system-widecapability of beacon self-detection. Scheme 400 thus effectivelyfunctions as a closed-loop system that continually measures, updates,and controls broadcasting APs. Because the beacon deployment accordingto scheme 400 allows for sufficiently fast communication and controlmeasures, central server 412 is further configured to sum measuredinterference to almost zero, thus effectively providing no significantinterference. Conventional protection schemes have not considered such azero-interference closed-loop system.

FIG. 5 is a schematic illustration of a satellite service protectionsystem 500 implementing protection scheme 400, FIG. 4, and similarcomponents between system 500 and scheme 400 function in a similarmanner to one another. In an exemplary embodiment, system 500 includesan FSS site 502 having a plurality of earth stations 504. In thisexample, FSS site 502 is a registered site. Each earth station 504includes a dish and a frequency agile receiver (not numbered), forreceiving and decoding video/data streams from a satellite 506. System500 further includes at least one or more existing APs 508 that havebeen authorized by, and are under the management and control of, acentral server 510 having a centralized database 512. Central server 510may include, or be, an SAS. System 500 further includes a new AP 514seeking authorization from central server 510 (e.g., under PAL or GAAterms).

In the exemplary embodiment, each existing AP 508 includes at least oneexisting beacon transmitter 516 as an integral component or functionthereof. In other embodiments, existing beacon transmitters 516 may beseparate and distinct components from corresponding existing APs 508.Similarly, new AP 514 includes a new beacon transmitter 518 as anintegral component or function of thereof (as illustrated), or as aseparate and distinct element. New AP 514 is in operable communicationwith central server 510 over new AP data link 520. In some embodiments,new beacon transmitter 518 is in operable communication with centralserver 510 over a separate beacon data link 522. In other embodiments,the beacon transmitter and the AP communicate with central server 510over a single data link, as illustrated with respect to existing AP datalinks 524 for APs 508. In the exemplary embodiment, each of beacontransmitters 516, 518 may include a transceiver (not shown), separatetransmitting and receiving components, and/or an omnidirectionalantenna. For ease of explanation, individual user equipment (UEs) thatmay be associated with APs 508, 514 are not shown.

New beacon transmitter 518 is configured to transmit a direct beaconsignal 526 for reception by one or more beacon detectors 528 at FSS site502. In the exemplary embodiment, FSS site 502 includes at least onebeacon detector 528 for each earth station 504, and in close proximityto the respective earth station. In an alternative embodiment, FSS site502 includes a single beacon detector 528 for a plurality of earthstations 504. In this alternative embodiment, the distance between thesingle beacon detector 528 and each individual earth station 504 isknown, and recorded in central database 512. A model for the FSS isbuilt so that the single beacon detector can model the interference toeach individual dish based on its operating parameters. Beacon detectors528 may be located indoors or outdoors, and may be integral to thestructure of a particular earth station 504 (e.g., earth station 504(1)and beacon detector 528(1)), or separate components (e.g., earth station504(2)/beacon detector 528(3), 504(3)/beacon detector 528(3)).

More specifically, in the example where beacon detector 528(1) is anintegral portion of earth station 504(1), beacon detector 528(1)utilizes LNB 530 as the effective receiving portion of the beacon signalreceived by the dish. That is, the dish of earth station 504(1) detectsdirect beacon signal 526 from beacon transmitter 518 along with thetransmit spectrum from satellite 506. LNB 530 demodulates direct beaconsignal 526 along with the received transmit spectrum (not shown in FIG.5), and distributes the demodulated beacon signal, according to anexemplary embodiment, along a distribution chain 532 to a rack ofreceivers 534 in a headend 536, to reach a reporter 538. In an exemplaryembodiment, reporter 538 is configured to filter and process thedemodulated beacon signal, and then report it to central server 510 overa first beacon measurement reporting link 540. In an embodiment, firstbeacon measurement reporting link 540 is a wired or wireless data link,or may be an RF communication. Thus, in this example, beacon detector528(1) utilizes reporter 538 effectively as the transmitting portion forthe beacon measurement.

In the exemplary embodiment, the MBP scheme further configures beacondetector 528 such that a determination may be made if the aggregatesignal level at the LNB input is greater than −60 dBm. In at least oneembodiment, this determination is based on summing the individualmeasurements of each transmitter within, for example, a 40 km radius ofFSS site 502. Beacon detection within system 500 is further configuredsuch that the system may further monitor (e.g., within FSS site 502, orexternally by central server 510) the current, output level, outputlinearity, and level of known input signal of the LNB. System 500 isfurther configured to measure noise level at the output of the feed horn(or filter unit) of the LNB, or alternatively, the carrier-to-noiseratio (CNR), the bit error ratio (BER), and/or another metric downstreamof the LNB that indicates noise floor impairment. In some embodiments,system 500 is further configured to determine degradation of the noisefloor at the intermediate frequencies, and/or degradation of receivermetrics that are attributable to the AP. For the CBRS band, having −129dBm/MHz as the expected protection level, −10 dB I/N may be sought asthe noise target. For other bands, a different noise target may besought.

The integrated configuration of beacon detector 528(1) is particularlyadvantageous to FSS sites having one or few earth stations, whereadditional hardware costs (e.g., additional antenna/transceiver for eachdish) might not be cost-prohibitive, or in the case where otherconsiderations would render multiple external antennas to beundesirable. Additional LNBs only marginally add to the hardware cost ofan earth station, and many earth stations often include multiple LNBsfor a single dish. The present embodiments therefore advantageouslyutilize one or more of the relatively less-expensive LNBs for beacondetection. According to this exemplary embodiment, system 500 is able totap into each FSS antenna signal distribution chain downstream of theLNB, and receive the beacon at the downconverted intermediate frequency(IF) frequency of the in-band beacon signal. According to thisadvantageous technique, the central server is able to avoid adjustingthe beacon RSSI for the FSS dish antenna gain, since the beacon signalis received utilizing the FSS dish itself.

The implementation of integrated beacon detector 528(1) provides thefurther advantage of enabling earth station 504(1) to detectinterference in exactly the way that the interference will be affectingthe earth station. In other words, any measured value at the reporter538 will exactly represent the value of the signal causing theinterference. In an exemplary embodiment, for narrowband signal, theintegral beacon detector 528(1) further includes a sufficiently stableclock for each such integral detector, to realize a more efficientdetection.

In some instances, and particularly for a narrow band signal, thefrequency stability of the oscillator used in the down conversionprocess in the LNB may be sufficient for a video signal, but may not byitself sufficiently stabilize the position of a beacon signal.Accordingly, in some embodiments, the local oscillator frequency usedfor down conversion may synchronize, for example, a GPS signal, suchthat the beacon signal is stabilized in order to speed the efficiency inwhich an auto-correlation of the beacon signal can be performed. Inother configurations of the beacon detectors described herein, anadditional clock (frequency) is not required for efficientfunctionality.

In the example where detection is performed by a component separate fromthe earth station, beacon detector 528 is an external antenna. In someembodiments, FSS site 502 includes up to one such external antenna foreach earth station 504. In other embodiments, FSS site 502 includes asingle external antenna for a plurality of earth stations 504 at thesingle FSS site. In the case where beacon detector 528 is an externalantenna located in close proximity to earth station 504, the beaconmeasurement reporting to central server 510 may be direct or indirect.More specifically, beacon detector 528(2) communicates directly withcentral server 510 over a second beacon measurement reporting link 542.In contrast, beacon detector 528(3) communicates first to a centralprocessor (not shown) of FSS site 502 over an internal site reportinglink 544, and FSS site 502 communicates directly with central server 510over a site status reporting link 546. In the exemplary embodiment, FSSsite 502 communicates additional site-related information, includingper-dish frequency usage, direction of alignment and elevation, dishsize, GPS co-ordinates, etc., to central server 510 over site statusreporting link 546.

This site related information, such as direction of alignment andelevation, can be provided dynamically to central server 510 bymeasuring devices (not shown) attached to each dish, and particularlyfor instances when the dishes are aligned to different satellitesfrequently. Alternatively, for dishes that are never moved once they arealigned, a database registration process (e.g., within central database512) could be used which does not need the expense of separatedynamically reporting measuring devices. In at least one embodiment, thesatellite measuring device includes a digital compass and/or anelevation angle-measuring component. In another embodiment, themeasurement device is similar to a computer-controlled measuring devicefor a telescope.

According to the exemplary embodiments illustrated in FIG. 5, centralserver 510 is capable of unlocking, for new AP 514, bandwidth that isunused by existing APs 516 (e.g., unused transmit spectrum portion 218,FIG. 2), thereby significantly increasing the spectrum utilization ofthe band. That is, as described above, not all of the twelve 40 MHzchannels in the transmit spectrum will actually be demodulated by everydish receiver distribution chain at every FSS site. System 500 thusadvantageously protects the “used” channels at the appropriate level ofco-channel protection, and assigns the conventionally “unused” spectrumto a new AP. In the exemplary embodiment, central server 510 furthercalculates blocking and noise levels to prevent degradation of FSSreceivers, using the empirical information obtained by the MBP scheme.

Furthermore, in addition to the improved spectrum utilization, systemsand methods according to the protection schemes described herein furtherachieve advantageous reductions to the geographic size of the protectionzone around an FSS site. That is, under current FCC protection schemes,an FSS site may be required to have a 150 km radius co-ordination zonewith formal written applications and studies carried out on eachtransmitter application against very conservative criteria. According tothe principles of the present embodiments though, the FCC protectionrules may be successfully changed to reduce the required radius of theprotection zone immediately about the FSS site, and may further createoutwardly-expanding geo-tiers of protection around new reducedprotection radius. For example, as described herein, an immediate firstprotection zone (i.e., an exclusion zone) around an FSS site may be setto a 150 m radius. A second geo-tier zone, outside of the firstprotection zone, may be set to a 320 m radius for small cell use, andfor operation within 280 MHz at 4 W transmitter power. A third geo-tierzone, outside of the second geo-tier zone, could then be set to a 780 mradius, and for operation within, for example, 500 MHz at 4 W. Beyond780 m, higher powers are available. These tiers may be further modifiedaccording to particular system specifications.

In the case where FSS site 502 includes a single beacon detector 528 fora plurality of earth stations 504, the single beacon detector 528 mayfurther implement multiple-input/multiple-output (MIMO) technology toeffectively increase the gain and extended the range of system 500 andthe protection scheme. In this example, a single beacon detectionantenna may provide greater system visibility around the environment,and may also represent a lower hardware cost outlay for an FSS sitehaving a large number of earth stations. Further to this example,because received interference will affect different earth stations indifferent ways, each of the plurality of earth stations 504 may furtherbe calibrated to the single antenna such that central server 510 isrendered capable of determining the effect of the interference on aspecific earth station 504, and then utilize the unique ID from theinterfering source to remedy the interference. Optionally, FSS site 502includes at least one distributed detector 548 in addition to one ormore beacon detectors 528.

In an embodiment, beacon transmitters 516 are transceivers, and arefurther configured to detect a direct beginning signal 526 overrespective RF paths 550, and report such measurement information tocentral server 510 over links 524. Accordingly, by utilizing individualbeacon transmitters for the dual-purpose functionality of transmissionand detection, system 500 is rendered capable of significantlyincreasing amount of real-time information that can be used to measure,manage, and remedy interference for a particular FSS site. Thiscapability is particularly advantageous in the case where FSS sites arenot densely populated (and thus potentially fewer available beacondetectors), but APs seeking to utilize the transmit spectrum are morenumerous. The APs themselves thus perform a level of self-policing amonga community of APs.

In an exemplary embodiment, such beacon transceivers can be implementedin either the hardware or the software of an eNodeB or AP, or mayconstitute a separate device having a separate antenna, or utilizing abase station antenna. In some embodiments, transmission of the beaconsignal may be periodic, on-demand, or according to programming. Wherethe beacon signal is managed according to a program, in at least oneembodiment, program may include instructions to terminate the beacontransmission once the eNodeB or AP has been authorized by the centralserver, but continue to allow beacon detection as desired. The beacontransmission program may be stored in a central database 512 and run bycentral server 510, or may be executed at the AP level. In someembodiments, central database 512 further includes data regarding thefrequency of satellite 506, one or more frequencies actually received byearth stations 504, as well as the direction of orientation andelevation of the earth station dish(es). All such information may beused to calculate initial resource allocations, as well as empiricalinterference management by central server 510.

FIG. 6 is a flow diagram for an exemplary process 600 for operatingsatellite service protection system 500, FIG. 5. In operation, process600 begins at step 602, in which small cell communication is initiatedby an AP. In one example of step 602, new AP 514 is a small cell accesspoint that initiates communication by one or more of powering up,restarting, wakening from a sleep mode, etc. In step 604, AP 514 submitsan authorization application to central server 510, including one ormore of a unique small cell identification code, location coordinates, arequested maximum power from the whole small cell, minimum powerlevel(s) for effective operation, a requested frequency channel orchannels, elevation, antenna and/or MIMO status, whether the AP use isindoor or outdoor, and an estimated maximal user number. In theexemplary embodiment, AP 514 communicates submitted information over awired Internet connection. In an alternative embodiment, AP 514communicates submitted information over the air by an agreed signalingchannel.

In step 606, central server 510 calculates a path loss based on apropagation model using the information submitted from AP 514 in step604. In at least one example of step 606, central server 510 furtherutilizes information previously stored in a central database 512 tocalculate the path loss. Once the initial path loss is calculated,process 600 proceeds to step 608. Step 608 is a decision step. In step608, process 600 determines, based on the calculations from step 606,whether unavoidable interference would result at any FSS earth stationfrom the operation of AP 514. That is, in step 608, central server 510determines whether there is a feasible channel and power level at whichAP 514 may provide effective coverage for small cell users and, at thesame time, will not cause interference to FSS site 502. In at least oneexample of step 608, the criteria for this interference determinationmay vary depending on the frequency of operation, the aggregatebackground noise level contribution, the number and distances of APs,etc.

If, in step 608, process 600 determines that interference will occur,process 600 proceeds to step 610. In step 610, central server 510rejects the application from AP 514. In further operation of step 610,AP 514 waits for a time period and then returns to step 604, where AP514 submits a new application to central server 510, including timelyupdated small cell information, or central server 510 informs AP 514 ofa change in conditions.

If, however, in step 608, process 600 determines that interference willnot occur, process 600 proceeds to step 612. That is, process 600determines that no interference occurs when central server 510calculates the existence of a maximum power level and a frequencychannel for AP 514 that will ensure both feasible and interference-freesmall cell communication. In step 612, central server 510 sendspermission to AP 514, including the approved frequency channel, theapproved maximum power, and other relevant operational information. Theapproved frequency channel/maximum power sent by central server 510 isthe same or different from the channel/power originally requested by AP514, based on calculations by central server 510 regarding the availablespectrum and/or measured empirical information that updates the initialpropagation model. In step 614, AP 514 transmits a beacon having acentral frequency derived from the approved frequency channel sent instep 612. In at least one example of step 614, the power level of thebeacon is also derived from, but will be significantly lower than, theapproved maximum power sent in step 612. In an alternative operation, AP514 transmits the beacon in an close adjacent guard band. The powerlevel of the beacon may thus be higher if the beacon is out of band, butnot high enough such that the FSS reaches −129 dBm/MHz. Spectral densityis a factor, and thus a beacon at 4 W/40 MHz could have higher power at100 kHz, for example.

In step 616, central server 510 collects data from one or more beacondetectors 528, including one or more of the received beacon power, thedetector coordinates, etc., and calculates a measurement-based path lossbased on the collected data. In the exemplary embodiment, the beacondata is additionally collected from beacon transmitters 516 with beaconreceiving functions, distributed sensing locations, or other in-rangedetection equipment that is communicatively coupled to central server510. In some instances, where the beacon cannot be detected by one ormore desired beacon detectors, central server 510 may use the datacollected from the other detector/sensing locations. In at least oneexample of step 616, central server 510 prioritize the collected beacondata according to the location of the detector (e.g., distance of adetector from a transmitter may be considered as a factor) and/or thereliability of the particular detection component (e.g., not alltransmitters and detectors will be of the same known quality). Once thepath loss is calculated, process 600 proceeds to step 618.

Step 618 is a decision step, and operates similarly to step 608. Thatis, in step 618, based on the calculated path loss from step 616,central server 510 determines whether unavoidable interference may occurat any FSS earth station(s) if AP 514 operates at the frequency channelthat was approved for beacon transmission, or in a guard band. That is,in step 618, central server 510 determines whether there is a powervalue at which AP 514 can provide effective coverage for particular UEsand, at the same time, will not cause interference to particular FSSsites 502. If unavoidable interference is foreseen, process 600 returnsto step 610. If the central server 510 determines that there exists amaximum power value that will guarantee feasible and interference-freeAP communication, process 600 proceeds to step 620.

In step 620, central server 510 sends permission to AP 514 with detailedinformation including an approved maximum power and an allocatedfrequency. Similar to step 612, based on calculations by central server510, the approved maximum power and/or the allocated frequency in step620 may be different from either or both of the requestpowers/frequencies from application step 604 or approval step 612.Process 600 then proceeds to step 622 in which AP 514 begins small cellcommunication at the approved frequency channel (e.g., from step 612 orstep 620) and approved maximum power level (e.g., from step 620), andcontinues the small cell communication for a communication period. Afterthe communication period, process 600 returns to step 604, where AP 514submits an application for revalidation, including updated information(e.g., the number of small cell users associated with AP 514).

Referring back to step 620, process 600 also proceeds to step 624, inwhich central server 510 updates its propagation model based oncollected measurement data from beacon detectors 528, beacontransmitters 516, and other detection components in the system, if any.

In step 626, small cell communication from AP 514 is terminated. Step626 occurs, for example, when AP 514 is placed into sleep mode, poweredoff (e.g., without sending an acknowledgement in time to central server510), or otherwise rendered non-operational. In various circumstances,step 626 may occur at any time in process 600 after step 602. Upontermination of small cell communication from AP 514, process 600proceeds to step 628, in which central server 510 determines that AP 514has ceased communication and any radiation/transmission at the protectedband. Process 600 then proceeds to step 624.

Process 600 is therefore particularly applicable to MBP schemes for FSSsites in the CBRS band/C-band and devices (e.g., CBSDs, APs, UEs, etc.)sharing the 3.55-4.2 GHz spectrum, as well as other bands where sharingradio resources is centrally enforced based on the interferencecontribution of individual transmitters and a spectrum sharing strategy.Furthermore, process 600 may add additional steps to those describedabove, or in some circumstances, omit particular steps that may becomeredundant or unnecessary in light of other conditions, or may beperformed in a different order. Additionally, process 600 may furtheradopt one or more of the following considerations.

In some embodiments, central server 510 is configured to determine if AP514 is within the required protection distance from any registered FSSsites, or within the coordination distance of existing APs. If AP 514 iswithin the protection or coordination distance, central server 510 mayinstruct AP 514 to activate its beacon transmitter 518. In someembodiments, as described above, beacon transmitter 518 may communicatedirectly with central server 510, and outside of the immediate controlof AP 514. That is, even in the case where the components are integral,AP 514 and beacon transmitter 518 need not directly communicate with oneanother. In such circumstances, the beacon link 522 and the AP data link520 to central server 510 may be separate and independent from oneanother.

In other optional features of system 500 and process 600, central server510 may be configured to pass the unique ID code to beacon transmitter518 for transmission over the air on a particular beacon frequency, andbeacon transmitter 518 may begin transmission using this ID code,assigned by central server 510, in its data payload. In an embodiment,the data payload may include one or more of the unique ID, the locationof beacon transmitter 518/AP 514, and the transmit power. In at leastone embodiment, the data payload further includes information related toUE utilization, as well as means to migrate interference of a UE to asatellite disk. For example, when a UE is determined to be too close inproximity to a protected FSS site 502, central server 510 may instructthe UE to change its frequency out of the protected band. Additionally,in the exclusion zones around an FSS site where any transmission isconsidered to cause interference, the UE may be instructed, withcoordination by the mobile core, to operate in another frequency band(e.g., 900 MHz).

In some embodiments, APs 508, 514 are further configured to directly orindirectly communicate information between one another about individualUEs associated with that respective AP. In at least one embodiment,according to particular operational conditions, such communicationoccurs over fixed network to reduce the payload of the beacon andmaintain a maximum link budget.

In some embodiments, central server 510 is optionally configured toproactively contact beacon detectors 528 that are within a protectiondistance, and inform the receivers thereof to report any beacon IDsreceived during an assigned measurement. In some instances, centralserver 510 may be optionally configured to directly contact selectedbeacon transceivers at a known nearby existing AP 508, as needed forGAA/PAL protection calculations, to initiate measurement of beaconsignal 526 from new beacon transmitter 518. The number of beacondetectors 528 disposed at FSS site 502 is optional, and may be based onmorphology, clutter, and expected propagation conditions. Similarly, theheight of the particular antenna, as well as its gain, may be assignedat the discretion of the operator. In some embodiments, a particularunique beacon ID may not be known to an FSS (e.g., where it may bedesired to protect the integrity of the beacon measurement scheme), butwill be stored in central database 512 for confirmation by centralserver 510 where necessary.

In some embodiments, central server 510 may also be configured (e.g.,through software programming or hardware components) to query amanagement system/processor (if known and/or present) of an FSS site toupdate information in central database 512 regarding bandwidth usage,antenna azimuth, elevation angle receiving schedule, noise measurements,etc. Similarly, beacon detectors 528 may be programmed (or may beresponsive to control by a program from another component) toautomatically report to central server 510, upon detection of any beaconID, the received beacon ID, the RSSI, and/or the signal-to-noise-ratio(SNR). Optionally, central server 510 may be further programmed to waitfor a timeout, and note if FSS site 502 has identified the beacon IDassigned to new AP 514 during a measurement period, and then update theFSS site parameters in central database 512 if such beacon informationhas been received.

In some embodiments, central server 510 is further programmed tocalculate the path loss between each AP 508, 514 and each FSS site 502for each beacon detector 528, and compute the potential for interferenceto each FSS site dish antenna. Such calculations may further considerthe received RSSI values, antenna azimuths, and gain patterns at boththe respective FSS sites and the APs, and further take into account thecomputed path loss between the AP and FSS site locations based on thediscrete and continual beacon measurements. Central server 510 may stillfurther be configured to calculate the path loss between new AP 514 andexisting APs 508, and calculate the potential for interference by new AP514 to each existing AP 508. In this example, such calculations mayfurther consider antenna parameters, FSS site parameters, and thecomputed path loss between AP's based on real-time beacon measurements.

In all of the examples described above, central server 510 is configuredto utilize the results of the beacon measurements, as well as updatesfrom the FSS site parameters, to continually monitor the operatingparameters for AP (and also UE) communication with respect to one ormore FSS sites. Such operating parameters include, without limitation,the power levels, antenna gain/orientations, and transmit frequency.

The systems and methods described herein therefore realize significantadvantages over the conventional protection schemes by allowing for thedetermination of the actual path loss between an AP/CBSD and an FSSsite, and also the loss from AP/CBSD to AP/CBSD. The present embodimentsthus achieve in-band beacon transmission-to-detection with greater thana 180 dB link budget (e.g., for a single AP) or up to 200 dB link budget(e.g., for multiple APs) for satellite dishes with low elevation anglesto Geo-stationary satellites. According to the present embodiments,measurement of third party signals by an AP (e.g., from knowntransmitters in the direction of the FSS site or other APs) furtherallows a significantly improved capability to estimate in-building lossand path loss distance-based exponents, as well as means for remedyinginterference. In at least one embodiment, a plurality of central serversare networked together to share information and complete tasks. In thisexample, the plurality of central servers may be supplied by differentcompanies and/or operators, work and communicate together in acloud-like network, and/or assign one central server as a master serverto manage other central servers.

The present systems and methods further allow for the determination ofthe individual interference contribution from each identifiedtransmitter. In some embodiments, the individual interferencecontribution may be determined using formats for narrow band beacons andreporting, such as weak signal propagation reporting (WSPR), forexample, in order to determine path loss within the gain profile of thesatellite aperture. The central server is able to prioritize and controlAP transmitter parameters to reduce the overall transmittercontributions such that they fall below the noise floor, and/or aparticular desired noise target for all the key interference thresholds.According to these advantageous capabilities, other transmitters outsideof the aperture can be successfully de-prioritized, multipathcontributions can be recognized and managed, and overall noiseoptimization can be obtained.

According to the present embodiments, further advantages may be realizedwith respect to mobile device management. For example, UEs associatedwith an AP/CBSD may contribute interference to an FSS site, even atrelatively low transmitter power. Under the protection schemes andsystems herein though, UEs may themselves deploy a beacon signal mannersimilar to that described above with respect to the APs, and thus moreeffectively report their association with a particular AP/CBSD, andhence the UE location (from the UE beacon or directly from the AP) tothe central server/SAS. Accordingly, the actual path loss associatedwith each UE may be determined, and thus the level of interference fromthat UE. If the interference from a particular UE is determined toexceed a chosen threshold, the AP may cause the UE to move to anotherband, such as the macro-cell which uses a different frequency band tothe satellite system and does not cause any interference.

In an exemplary embodiment, the AP (or CBSD) reports a number of UEsassociated with that particular AP such that the effective transmitterpower is proportionally increased to that of the number of UEs, and inconsideration of the transmitter power of each individual UE. If thiseffective transmitter power becomes too high, that is, causes apotential interference problem, then the individual UEs may beinstructed to operate in another band, such as a macrocell. In thisexample, the individual UEs would not be required to utilize the beacontransmissions, since the range of association distance between the UEand the AP is considered relatively small in comparison with thedistance of the AP to the FSS site. Therefore, utilization of accurateapproximations for these individual UEs (in close association distance)renders optional this use of the beacon technology at the individual UElevel.

The systems and methods herein further advantageously provide FSS sitemonitoring and reporting to the central server of real-time channelusage at each FSS receiver/dish pairing. Under these techniques,receiver frequency assignment can be fixed or dynamic, depending onsatellite and FSS customer needs, and such assignments may becontinually tracked by the central server to prevent interference byCBRD, Radio Access points, UEs or other interfering devices. FSSreceiver bandwidth may therefore be automatically detected, oralternatively, manually input if desired.

When the actual received bandwidth is known at each location andsignaled to the central server, the full 500 MHz transmit band will notneed 180 dB or 200 dB of co-channel protection from the CBRS fundamentalemission. Instead, as little as 104 dB of protection may be adequate toprotect FSS to the FCC-mandated level, such as for the second adjacentband. Furthermore, the multi-protocol receiver may be installed at FSSdish to identify CBSD signal sources and report RSSI and identificationdata to central server. In this example, these co-channel protectionvalues are included for illustration purposes, and not in a limitingsense. These values may reflect upper limits for satellites with lowelevation angles within the central beam, but may which have smallbeamwidth angles. The 180 dB value may therefore be representative of asingle AP, and may be greater (e.g., the 200 dB value) for multiple APswithin the central beam. Interference falling within the central beamangle (e.g., 3 degrees) is of greater significance than interferenceoutside of the central beam. That is, a greater number of APs may bepermissible nearer the FSS site, but outside of the central beam angle.

As described herein, the central server is configured to act to not onlyapprove applications to transmit, but also to monitor, measure, manageactive participants, and further to remedy potential and actualinterference. The central server of the present systems and methods thusacts upon bandwidth usage reporting by the FSS sites and themeasurement-based protection scheme system. Measurements by beaconreceivers, multi-protocol receivers, FSS satellite program receivers,other APs/beacon transmitters, and even UEs, are reported to directly orindirectly to the central server to determine one or more of: (i) pathloss between the FSS site and the AP/CBSD; (ii) path loss between theFSS site and a UE associated with the AP/CBSD (e.g., with locationinformation); (iii) path loss between a new AP/CBSD and one or moreexisting APs/CBSDs; (iv) impairment of the FSS noise floor; (v)degradation of FSS receiver performance; (vi) the identify of aparticular AP/CBSD that is raising the noise floor at a specificfrequency and for a particular FSS site dish; (vii) any interferencecaused by a UE in close proximity to the FSS site; and (viii)interference from the aggregation of transmitters across the wholesatellite band that impacts on the linearity of the LNB.

According to the present embodiments, central server is still furtherconfigured to take one or more of the following remedial measures tomitigate interference and migrate the source of interference to anon-interfering communication status: (i) collect input information anddetermine appropriate actions to take regarding interferingAPs/CBSDs/UEs; (ii) issue commands to AP/CBSD to modify operatingparameters (e.g., transmit power, operating frequency/bandwidth, antennapointing angle or direction, etc.) of new and existing APs/CBSDs basedon FCC rules, equitable resource allocation calculations, changes to RFpropagation, etc.; (iii) issue commands to specific UEs (in conjunctionwith an associated mobile network or other networks) to modify operatingparameters, including changing channel of operation (e.g., in the caseof a mobile network, to that of the macro-cell that is in a differentband to the FSS site); (iv) continually monitor the operation of aninitialized AP/CBSD over time for changes in propagation conditions andother factors could change the interference environment; (v) regularlymonitor status reports from FSS receivers and/or master schedulerregarding bandwidth utilization at each site, and recalculate resourceallocation values using this updated information; and (vi) modifyfrequency assignments of existing APs/CBSDs in an impact area of FSSsite according to changes in FSS frequency usage.

A person of ordinary skill in the art, upon reading and comprehendingthis written description and accompanying drawings, will understand theapplicability of the present embodiments beyond the specific examplesdescribed herein. For example, the principles of spectrum sharing in theC-band and CBRS band may be applied to protection schemes in otherbands, and particularly to the “6 GHz” bands, namely, the 5.925-6.425GHz and the 6.425-7.125 GHz bands, which are presently utilized forsatellite uplinks. Such innovative 6 GHz band protection schemes aredescribed immediately below. The present inventors further envisionimplementing the advantageous beacon detection systems in a “stoplight”system for governing the deployment and operation of particular beacondetectors.

Beacon Based Protection for the 6 GHz Band Spectrum

As described above, the disclosed beacon protection system isparticularly useful for sharing the 3.6-4.2 GHz spectrum between the FSSearth stations and other terrestrial radio system users. The followingembodiments describe innovative systems and methods for extending theseinnovative techniques to the 5.925-6.425 GHz spectrum, sometimesreferred to as the “designated 6 GHz” spectrum.

A key difference between the 3.6-4.2 GHz spectrum and the 6 GHz spectrumis that the 3.6-3.7 GHz and 3.7-4.2 GHz spectra are used to receivesignals from space, whereas the 5.925-6.425 GHz spectrum is used forearth-to-space communications. The 6 GHz spectrum thus involvesdifferent propagation physics that are associated with the protection ofthis particular spectrum range, and also includes different usersdesiring to share this portion of the spectrum. For example, at present,in the United States, the 5.925-6.425 GHz spectrum has approximately27,000 or greater microwave point-to-point users. Additionally, the 6GHz spectrum is significantly less suited for use by mobile users,which, in the main, is the 3.6-4.2 GHz spectrum. However, although the3.6-4.2 GHz spectrum is presently targeted for 5G mobile use, the3.6-4.2 GHz spectrum has relatively fewer available microwavepoint-to-point links.

Although the following embodiments are described with respect toextending the beacon protection techniques, described above, to the 6GHz spectrum, the person of ordinary skill in the art will understand,upon reading and comprehending the present specification and drawings,that these innovative techniques may be further extended into othersatellite bands and spectra for future shared use. The followingembodiments provide a solution to a recently-proposed challenge, whichrecommend portions of the 3.7-4.2 GHz spectrum, presently used forsatellite downlinks, be allocated for licensed mobile communications,while designating the 6 GHz spectrum (5.925 to 7.125), which includesthe uplink counterpart, for unlicensed use. One recent proposal is tofree 1700 MHz of spectrum: 500 MHz for licensed purposes; and up to 1.2GHz for unlicensed purposes. The systems and methods herein extend thebeacon-based protection techniques, described above, will advantageouslymanage sharing of this new proposed usage of the 6 GHz spectrum in asignificantly more efficient manner.

The 6 GHz Spectrum (5.925-7.125 GHz)

In the United States, the 500 MHz of bandwidth in the 5.925-6.425 GHzband (hereinafter, the “Lower 6 GHz” band) of the 6 GHz spectrum ispresently allocated exclusively for non-federal usage, on a primarybasis for FSS (Earth-to-space) and fixed services (FS). Similarallocation of the Lower 6 GHz band is implemented across the world.

For the FSS uplink, the 5.925-6.425 GHz band (Earth-to-space) isassociated with the 3.7-4.2 GHz band downlink (space-to-Earth), whichare collectively referred to as the “C-band” in conventional parlance.In this application, the conventional parlance is used for ease ofexplanation, and is not intended to be limiting. That is, a person ofordinary skill in the art will understand that, by “C-band,” the presentembodiments are intended to generally refer to the 3-8 GHz spectrum, andsatellite systems and/or mobile communication systems that operatewithin this spectral range, and frequently with respect to similarsystem elements/components (e.g., satellite dishes, earth stations,transmitters, receivers, APs, UEs, etc.). Moreover, the person ofordinary skill will understand that the systems and methods herein arenot limited to only the particular spectral ranges, or portions thereof,described herein.

At present, there are approximately 1,535 earth station licenses in the5.925-6.425 GHz band. Although most of these earth stations operate atfixed locations, some earth stations have been disposed on mobilevessels but still operate in this band on a primary basis. In at leastone instance, mobile devices of one operator have been licensed totransmit to geostationary satellites in order to provide consumer-basedtext messaging, light email, and Internet of Things (IoT)communications, thereby protecting terrestrial operations by using adatabase-driven, permission-based, self-coordination authorizationsystem. At present, the 5.925-6.425 GHz band is also used for thetransmission of command signals transmitted by the earth stations,typically near 5.925 or 6.425 GHz.

In present FS implementations though, the 5.925-6.425 GHz band isheavily used. FS licensees are, for example, authorized to operatepoint-to-point microwave links with up to 120 MHz of paired spectrum foreach authorized path. Individual paired channels under these licensesmay be assigned in specified bandwidths ranging from 400 kHz up to 60MHz. Present public records indicate that greater than 27,000 licenseshave been issued for point-to-point operations in this band. Suchoperations are known to support a variety of critical public services,such as public safety (including backhaul for police and fire vehicledispatch), coordination of railroad train movements, control of naturalgas and oil pipelines, regulation of electric grids, and backhaul forcommercial wireless traffic.

At present, the 5.925-6.425 GHz, or Lower 6 GHz, band portion of the 6GHz spectrum is the most heavily used FS band for long links, withapproximately 63,260 transmit frequencies in use. The lower 6 GHz bandis otherwise known to only provide significant applications for FSSuplink earth stations. However, because FSS uplink earth stations do notconventionally include receiver capabilities at the 6 GHz spectrum, theFSS uplink earth stations presently would not require protection fromthe FS usage.

Accordingly, it is presently easier to coordinate with earth stations at6 GHz than it is to coordinate at 4 GHz, because there are fewer earthstations to consider in the 6 GHz spectrum. Moreover, because thetransmitters are at a higher frequency (6 GHz) than the receivers (4GHz), other users of the 6 GHz spectrum implement highly directionalsystems that often exhibit lower gain in comparison with FSS in the 4GHz band. Thus, many earth stations at the 4 GHz spectrum are configuredto receive-only. Furthermore, coordination zones for the 6 GHz spectrumare respectively smaller, and a 6 GHz FS operator is better able toaccept the risk of incoming interference from an uplink earth station.Additionally, many 6 GHz earth stations are configured to transmit toonly one transponder on one satellite for decades at a time. An FS userhas been able to conventionally assume that other frequencies andpointing directions will remain vacant. In contrast, at 4 GHz, the FSuser is required to always protect even portions of the band and arcthat its particular earth station does not use, and/or is never expectedto use.

Nevertheless, 6 GHz uplink earth stations still have the potential tocause interference to FS receivers. As with the 4 GHz downlink earthstations, the 6 GHz uplink earth stations always have the right tooperate on any frequency in the band, pointing to anywhere in the entiregeostationary arc thereof, at any time and without notice. Therefore,even though it is easier to site FS links for reliable operation at 6GHz than it is at 4 GHz, potential interference problems still remain.

Remaining portions of the 6 GHz spectrum are defined by the FCC Noticeof Inquiry (NOI). That is, the NOI further describes the 6.425-7.125 GHzband to include three different segments, with each segment having adifferent respective application.

The first segment of the 6.425-7.125 GHz band is the 6.425-6.525 GHzsegment. The 6.425-6.525 GHz segment has a mobile allocation withBroadcast Auxiliary Service and Cable TV Relay applications. The6.425-6.525 GHz segment presently has no FS allocation, and therefore nopublic position regarding the use of the 6.425-6.525 GHz segment hasbeen taken by the Fixed Wireless Communication Coalition (FWCC).

The second segment of the 6.425-7.125 GHz band is the 6.525-6.875 GHzsegment (hereinafter the “Upper 6 GHz” band, or FS band). At present,the upper 6 GHz band is used less intensively by earth stations, but hasa narrower bandwidth than the Lower 6 GHz band. Only in the past fewyears have operators been able to use Upper 6 gigahertz band channelshaving a bandwidth wider than 10 MHz. In contrast, the Lower 6 GHz bandhas had available 30 MHz channels for many years, and more recently, 60MHz channels. Because of these considerations, the Upper 6 GHz band hasexperienced significantly less total activity than has the Lower 6 GHzband, and using approximately only half as many transmit frequencies.The usage of these upper 6 GHz band though, is growing, in the presentembodiments offer advantageous solutions to successfully manage thisincreased usage.

The third segment of the 6.425-7.125 GHz band is the 6.875-7.125 GHz(hereinafter, the “7 GHz” band), which primarily serves the BroadcastAuxiliary Service and the Cable TV Relay Service, similar to the firstsegment. In contrast to the first segment, however, FS links arepermitted in the 7 GHz band, but these FS links are not permitted tointersect with the service areas of television pick up. Such limitationshave thus severely restricted FS access in the 7 GHz band. Similar tothe first segment though, the FWCC also has not stated a public positionregarding future usage of the 7 GHz band.

The systems and methods herein therefore advantageously utilize the 6GHz band to address considerations arising from the reallocation of theformer 2 GHz FS band, and also in consideration of the problems,discussed above, experienced in coordinating with FSS earth stations at4 GHz. The present Upper and Lower 6 GHz bands/band segments thusrepresent the only remaining FS bands that implement frequencies lowenough to span tens of miles. These two band segments are discussedtogether herein because they have similar technical characteristics andare used for similar purposes. These two band segments are furtherdiscussed together because the FS links in both segments (at present andfor expected future use) will require the highest levels of protectionfrom other services.

The present systems and methods additionally allow devices toadvantageously operate both in the lower 6 GHz band and in the spectrumdesignated (by the FCC) for Unlicensed National InformationInfrastructure (U-NII) use. Because the lower 6 GHz band is consideredclose to the U-NII spectrum, the extension of the present beacondetection schemes to the 6 GHz band provides a technical solution tobeneficially enable U-NII devices to flexibly operate in both spectra.Such devices may thus operate with wider channel bandwidths and higherdata rates. Such devices would also realize a significantly increasedflexibility for all types of unlicensed operation.

As described herein, “U-NII devices” refers to unlicensed devices thatpresently operate in the 5.15-5.35 GHz and 5.47-5.725 GHz bands. Asunlicensed devices, such U-NII equipment operates under Part 15 rules ofthe FCC. Devices that operate pursuant to Part 15 generally sharespectrum with allocated radio services, and therefore must operate on anon-interference basis, that is, such unlicensed devices are notpermitted to cause harmful interference, such as from allocated radioservices and authorized users. Such unlicensed devices are furtherrequired to meet technical requirements or standards designed tominimize the risk of harmful interference. Manufacturers though, enjoysignificant flexibility with regard to the hardware and applicationsthat may be implemented to satisfy these technical requirements, whichhas contributed to the significant recent growth of various technologiessuch as Wi-Fi.

In 2013, the FCC proposed to make additional spectrum available forU-NII devices in the 5.35-5.47 GHz and 5.85-5.925 GHz bands, but theNational Telecommunications and Information Administration (NTIA)concluded in 2016 that there is no viable solution for U-NII devices toshare the 5.35-5.47 GHz band with incumbent federal systems. The presentsystems and methods avoid this problem by providing spectrum sharingtechniques that allow U-NII devices to operate in the 6 GHz band.

The present embodiments further advantageously allow for coordinationwith existing fixed microwave frequencies, which has proven difficultfor conventional systems. The present embodiments still further enablecoordination with developing cm- and mm-Wave 5G system technology. Atpresent, a fixed microwave applicant coordinates a particular frequencyband and a particular azimuth. All other frequencies and directions arethus available to other applicants. In comparison, to coordinatesatellite earth station frequencies, an FSS applicant will routinelycoordinate the entire band, as well as every pointing direction towardevery geosynchronous satellite. By default, the FSS implementations usefull-band and full-arc coordination, even if accessing only onetransponder on one satellite, and fixed microwave applicants mustprotect even unused satellite coordination. The difficulties of thefixed microwave coordination are illustrated below with respect to FIGS.7 and 8.

FIG. 7 is a graphical illustration depicting a comparison ofconventional fixed point-to-point distributions 700 and 702, for the 4GHz band (downlink) and Lower 6 GHz band (uplink), respectively. Asillustrated in FIG. 7, both distributions 700 and 702 representfull-band, full-arc, and fixed microwave links. Distribution 700illustrates how the 4 GHz band presently includes approximately 939 ofsuch links, whereas distribution 702 illustrates how the Lower 6 GHzband includes approximately 57, 654 of such links.

A comparison of distributions 700 and 702 further illustrates theapplicability of the present techniques with respect to exclusion zones.Distribution 700, for example, demonstrates how the downlink exclusionzones are very large and difficult to avoid, thereby resulting in fixedmicrowave implementations being barred from significant portions of thegeographical territory. Distribution 702, on the other hand,demonstrates how uplink exclusion zones are considerably smaller incomparison, and easier to avoid. Nevertheless, in the uplink, isconsidered risky under conventional techniques to use vacant channels inan FSS protection/exclusion zone.

FIG. 8A is a graphical illustration depicting a conventional earthstation location 800 for the 4 GHz downlink band. FIG. 8B is a graphicalillustration depicting a conventional comparison plot 802 of a trend 804(shown in yearly increments) of the number of fixed microwave earthstations in the 6 GHz uplink earth station transmit band and a similartrend 806 of the fixed microwave earth stations in the 4 GHz downlinkband. As can be seen from FIGS. 8A-B, fixed microwave coordination at 4GHz is conventionally considered to be impossible over much of thecountry. The beacon detection scheme described above though, solves thisproblem by providing a fixed microwave coordination scheme at 4 GHz.However, as described further below, this innovative beacon scheme maybe even further extended for shared use applications in at least thedesignated 6 GHz band.

FIG. 9 is a graphical illustration of a chart 900 depicting relativepercentages of existing earth station database problems conventionallyencountered, such as earth stations being (i) more than 100 feet fromlicense, (ii) built and decommissioned, or (iii) not found. Based on asample of 300 earth stations to determine usage of registered earthstations, chart 900 demonstrates a relatively low utilization (35%, inthis example) in the FCC database. It should be noted though, that chart900 does not take into account usage of unregistered earth stations.Nevertheless, chart 900 is based on an FWCC study that has been crediblyconfirmed by other studies.

Conventional interference mitigation techniques have been unable tofully resolve these problems. A collaboration of Working Parties of theInternational Telecommunication Union (ITU) drafted a recommendation forpotential mitigation techniques to improve operation of InternationalMobile Telecommunications (IMT) in the 3.4-3.6 GHz band without causinginterference to FSS earth stations, but the working parties have notreached a jointly approved solution. The ITU Radio Communication Sector(ITU-R) has proposed several other techniques to mitigate interferencewith coexisting terrestrial and satellite systems in the C-band(assuming a maximum EIRP of 59 dBm for terrestrial systems), but none ofthese proposed techniques have effectively overcome the basicincompatibility between IMT systems and FSS earth stations. The beacondetection techniques of the present embodiments, on the other hand,successfully resolve these known incompatibilities, and within theparameters described herein.

Band segmentation, for example, has been proposed as one conventionalsolution for terrestrial service/satellite system coexistence.Real-world deployments, however, have conclusively shown that harmfulinterference may still occur even when the two respective systemsoperate in non-overlapping bands. One particular study indicated that a2 km separation distance from all satellite receivers was conventionallynecessary to prevent terrestrial mobile systems from causing harmfulinterference. This harmful interference arises due to the limitedcapability of (i) terrestrial systems to limit out-of-band emissions,and (ii) satellite receivers to filter out unwanted emissions inadjacent bands.

Additional filtering techniques have been proposed to address theseadjacent band problems, but such additional techniques have also beenunable to successfully manage the terrestrial/satellite coexistence. Twointerference mechanisms are particularly related to these adjacent bandproblems: (1) unwanted emissions from terrestrial base/mobile stations(e.g., operating in the C-band) can generate interference to earthstations in other parts of the same band; and (2) since the LNBs andLNAs used on FSS earth stations are designed to receive a broad spectrum(i.e., including the entire C-band), the power radiated by terrestrialbase/mobile stations can overdrive the respective amplifier of the firstblock, thereby compromising the linear response thereof. This overdriveeffect on the LNB is reduced by including additional filtering (e.g.,bandpass, etc.) on the FSS earth stations, however, the application ofsuch additional filtering to the FSS earth station would prevent thestation from using portions of the C-band, which would compromise theservice thereof.

Moreover, additional filtering solutions are difficult to apply in thecase of transportable earth stations, since, by the nature of theiroperations, the geographical location and receiving frequencies of thetransportable earth station may vary significantly and often over time.A typical Satellite News Gathering (SNG) earth station, for example, maybe employed to transmit and receive carriers on different satellitetransponders, from the number of different geographical locations, in arelatively short interval of time. Furthermore, the introduction of anRF filter between the FSS earth station antenna output and the input tothe amplifier of the first receiving block Will generate loss.Consequently, the system equivalent noise temperature will increasesignificantly for any 0.1 dB of attenuation, on the order ofapproximately 2.3-8%.

Filters that are conventionally used in the C-band are known to have aninsertion loss of approximately 0.5 dB, thereby resulting in an increasein the noise temperature on the order of approximately 43%, or 1.54 dB.Additionally, an increase to the satellite downlink carrier EIRP willresults in a reduction to the overall capacity of the satellite system.Because many FSS earth stations are receive-only, and thus arefrequently unlicensed or “blanked licensed,” the inability of a systemadministrator to have access to all of the necessary information placesfurther practical constraints against the application of additionalfiltering to the FSS earth station. Another conventional filteringtechnique addresses the interference from unwanted emissions by applyingrejection filtering to the transmitting terrestrial base/mobilestations. This technique reduces emissions outside of the assignedfrequency blocks, but interference is still known to occur within aseparation distance of up to approximately 4 km.

The deficiencies in these conventional proposals are resolved accordingto the innovative techniques of the systems and methods herein, whichdynamically allocate the spectrum between the respective terrestrial andsatellite systems. Under these dynamic spectrum access solutions,terrestrial systems within a given territory are enabled to use theportions of the spectral band that are not being used by ground-basedsatellite systems in the vicinity. According to these advantageoustechniques, terrestrial systems are effectively able to “choose” theappropriate frequency of operation, according to the real-timeinformation collected through the disclosed auxiliary system, whichincludes a network of beacons installed on the FSS earth stationantennae, and/or a database with geographical data.

As described for the downlink 4 GHz/C-Band embodiments, above, the FSSreceiver is highly sensitive to interference from other users. In thisembodiment though, the above dynamic spectrum techniques are furtheradapted to additionally protect the 6 GHz band, where the FSStransmitter potentially creates interference to other users. That is,according to the embodiments described herein, systems and methods areprovided that advantageously protect both a particular FSS from others'interference, and others from potential interference from the particularFSS. As described further below, both techniques largely employ the sameinfrastructure.

Therefore, the present solution protects not only users of the downlink(e.g., multiple system operators (MSOs) of a cable network, contentproviders, etc.), but also other users that may be affected by theuplink transmissions. By providing such two-way protection using largelythe same beacon detection/transmission subsystem overlay to existingnetwork infrastructures, the present embodiments vastly expand theprotection that may be implemented with respect to the severalcommunication bands, but without significantly increasing theimplementation costs in proportion thereto. Using this subsysteminfrastructure, the present inventors contemplate that the innovativetechniques described herein may be further extended into othercommunication bands according to the same scale of economy.

Previous auxiliary information systems have been proposed, but thedesign and implementation of such conventional auxiliary systems wascomplex, and the required maintenance thereof very expensive. Incontrast, the beacon detection system of the present embodiments isintegrated, in a relatively inexpensive manner, within the existing theFSS infrastructure. Through this innovative integration, a real time,measurement-based propagation is determined, which allows exclusionszones to be reduced to as little as only a few hundred meters in radius,e.g., for the circular portion of the “teardrop shape” of a typicaltransmission. Furthermore, even in the pointed portion (i.e., in thedirection of transmission) of the teardrop shape, the beamwidth thereofwill be relatively narrow, thus providing for a significant reduction tothe total exclusion zone area in comparison with conventionalapproaches. This dramatic reduction to the size of the exclusion zonesalso results in a comparable increase to the value of the spectrum.

The reliability of the present embodiments is achieved according to thesimplified architecture of the auxiliary beacon detection system, aswell as the built-in capabilities to verify the accuracy of thereal-time measurements of a particular beacon from a number of otherbeacons within range. In a given geographical area, the manager of therespective terrestrial system is required to decide whether abase/mobile station may transmit or mute any transmission on the basisof the information concerning the real-time usage of the C-band by FSSearth stations in the surrounding area (and then continue to update suchdecisions). Accordingly, the correct functioning of the auxiliarymeasurement system, as well as the timely accuracy of the information itdelivers, is of great significance to prevent interference between thesystems.

The operational requirements of FSS downlink earth stations aregenerally subject to constant and rapid variations. Accordingly, tomaximize flexibility in response to such variation, the earth stationsare generally designed to receive multiple carriers of bandwidth, andtypically between 4 kHz and 72 MHz in portions of the C-band.Additionally, the frequencies at which a particular earth station mayoperate, and the pointing direction of the respective earth stationantenna, are not fixed; the frequencies and pointing directions may alsobe varied at any given point in time by the respective satelliteoperator according to a number of various operational circumstances,many of which may be unforeseeable. The present embodiments thereforeprovide an innovative solution that advantageously allows earth stationsto access the entire space segment, such that the earth stations mayrespond without any disruption to changes in operational conditions,which often occur instantly and without notice.

As described further below with respect to FIG. 10, the present systemsand methods implement a closed loop system that is capable of planning,monitoring, and controlling interference in a dynamic manner. Thisdynamic closed loop system advantageously allows shared use of therelevant spectrum among competing users to achieve the maximum commodityof the available spectrum. The innovative approaches described hereinmeasure propagation losses in real-time, thereby avoiding the use ofconventional propagation planning tools that are known to beintrinsically inaccurate. The measurement-based propagation techniquesof the present embodiments further avoid the limitations of conventionalshared-use planning, which utilized propagation tools that were requiredto make very conservative data assumptions in order to protect the mostsensitive user of the particular system being planned. That is, theconventional propagation techniques necessarily introduced significantinefficiencies to the spectrum abuse by being forced to allocate thespectrum according to the requirements of only the most sensitive user.

FIG. 10 is a schematic illustration of a shared use system 1000. In theexemplary embodiment, system 1000 includes an FSS site 1002, a centralserver 1004, a first FS transceiver 1006 (or a transmitter/receivercombination) including a first beacon transmitter 1008 and a firstbeacon detector 1009, a second FS transceiver 1010 including a secondbeacon transmitter 1012 and a second beacon detector 1013. In theexemplary embodiment, FSS site 1002 includes at least one beacondetector 1014. In the example illustrated in FIG. 10, first beacontransmitter 1008 is located within the vicinity of a plurality (i.e.,1-n) of neighboring APs 1016 (e.g., Wi-Fi access points), and eachneighboring AP 1016 includes a respective neighboring beacon transmitter1018. In this example, elements of system 1000 are similar to elementsin protection scheme 400, FIG. 4, and system 500, FIG. 5, and that aredesignated by similar labels. One of ordinary skill in the art willappreciate that additional elements from FIGS. 4 and 5 may beincorporated into system 1000 as described above, but that not all suchelements are repeated in FIG. 10 for ease of explanation.

In the exemplary embodiment, first FS transceiver 1006 operates apoint-to-point microwave link 1020 with second FS transceiver 1010, andcentral server 1004 receives fixed network data communications 1022(e.g., LAN, WAN, Internet, another type of electronic network, etc.).Additionally, first FS transceiver 1006 may be in operable communicationwith central server 1004 over a first data link 1024, and second FStransceiver 1010 may be in operable communication with central server1004 over a second data link 1026. Similar to the embodiments disclosedwith respect to scheme 400 and system 500, above, each of respectivebeacon transmitters 1008, 1012, and 1018 over beacon links 1028. System1000 may further include an FSS reporting link 1030 for communicatingoperating parameters of FSS site 1002 with central server 1004.

In the exemplary embodiment, central server 1004 is in operablecommunication with the beacon detectors 1009, 1013, 1014 to receiveinformation regarding detected beacon transmissions. Central server 1004may further be in operable communication with relevant transceiverportions (not separately shown) of APs 1016 that are configured todetect neighboring beacon transmissions, e.g., over beacon links 1028.In some embodiments, beacon links 1028 are configured as fixedcommunications, and may share the same link (e.g., fixed network datacommunications 1022) used to authorize transmission. In an embodiment,first and second data links 1024 and 1026 also, or alternatively, arefixed communications included in fixed network data communications 1022,which may represent a broadband fixed link or a radio link (e.g., amobile base station in a rural area, where a fixed cable link is verycostly, and all communication to and from the base station is instead byway of a point-to-point microwave link). Accordingly, fixed network datacommunications 1022 may represent a separate fixed link, or theaggregation of all fixed links where individual system components do notcommunicate over their own RF path.

In operation of system 1000, operation of FSS site 1002 within thevicinity of first FS transceiver 1006 generates FSS interference 1032(or potential interference) into the operation of FS transceiver 1006from the satellite uplinks (not separately shown) associated with FSSsite 1002. In a related manner, operation of neighboring APs 1016 withinthe vicinity of first FS transceiver 1006 generates Wi-Fi interference1034 (or potential interference) into first FS transceiver 1006 from therespective Wi-Fi operations. Each of respective beacon transmitters1008, 1012, and 1018 otherwise operates according to the principlesdescribed above.

That is, in the example illustrated in FIG. 10, the auxiliarymeasurement-based techniques of the downlink system are advantageouslyadapted for the uplink embodiment of system 1000 to enable the shareduse of the Lower 6 GHz band for microwave point-to-point FS andsatellite uplinks. As described above, the 500 MHz bandwidth of theLower 6 GHz band in the United States is allocated exclusively fornon-federal use, on a primary basis for FSS (Earth-to-space), and forFS, such as microwave point-to-point, and FS licensees may be authorizedto operate point-to-point microwave links with up to 120 MHz of pairedspectrum for each authorized path.

In accordance with system 1000 though, each user of the Lower 6 GHzspectrum, for both FSS (e.g., FSS site 1002) and FS (e.g., first FStransceiver 1006, second FS transceiver 1010), incorporates a radiobeacon (e.g., beacon transmitters 1008, 1012, beacon detector 1014) aspart of the transmission of the user's spectrum utilization. Therespective radio beacon thus uniquely identifies each respective user orneighbor as the potential source of interference. Also similar to theembodiments described above, the beacons may be included within guardbands, co-channels, or the unused portion of the 500 MHz of bandwidth inthe Lower 6 GHz spectrum.

In some cases, a Wi-Fi AP (e.g., AP 1016) is located indoors andoperates at low power (e.g., ≤1 W), system 1000 may be configured suchthat it may disregard, or give lower priority to, a beacon transmissionfrom the low power AP. According to an exemplary embodiment, such lowpower, “non-interfering” (i.e., low risk of potential interference) APsmay be exempt from including their own beacon transmitters. In contrast,Wi-Fi APs located outdoors, and employing higher power transmissions,could be required to include at least one beacon transmitter configuredto operate according to the principles described herein, since suchoutdoor/high power operation represents a significantly higher risk ofpotential interference. Overall system costs may be reduced by exemptingcommon, known, indoor, low power, low-risk APs.

In an alternative example, the effect of large number of indoor Wi-FiAPs in a cluster may collectively increase the potential risk ofinterference, even where individual ones of the cluster might not. Inthis case, system 1000 may be further configured to model such clustersas a single effective AP 1016. Where central server 1004 determines thatthe cluster AP 1016 represents an interference risk, central server 1004may be further configured to cause small decreases in the transmitterpower of all APs in the cluster to reduce the interference risk. In thisexample of system 1000 illustrated in FIG. 10, central server 1004 isconfigured to individually communicate with each AP in the cluster. Inother embodiments, central server may communicate with a primary AP inthe cluster, and the primary AP communicates with other, secondary, APsin the cluster. As described above, each AP may also include its ownbeacon detector.

In one embodiment, the transmitter power of the single cluster AP iscalculated using the MBP model for each individual transmitter of therespective low power APs in the cluster. This calculation is ofparticular value in the formation of an optimization strategy forresource assignment of or to the individual APs in the cluster. Thecentral server is thus further advantageously capable of re-optimizingthe transmitter powers, using the MBP measurement(s), as conditionsdynamically change. In another embodiment, the aggregate power of thecluster is directly measured, without necessarily identifying theindividual contribution thereto of each AP in the cluster. By thesetechniques, system 1000 provides further benefits over conventionalsystems in that central server 1004 may thus advantageously enablefrequency planning of individual Wi-Fi APs, to improve servicetherebetween, such as through the assignment of different channels toavoid interference between the respective neighboring APs. In someinstances of indoor AP use, the beacon detection range for the indoor APmay be limited. Nevertheless, in such cases, the indoor AP may bemanaged such that it has sufficient power to report to nearbyneighboring APs to enable central server 1004 to build up a map ofpotential interference that includes such indoor APs.

Thus, as with the downlink embodiments described with respect to scheme400 and system 500, the beacon transmission scheme of the uplink system1000 enables the identification of the registered transmitter bytransmitting the unique ID of the transmitter in a beacon. Also similarto the downlink beacon implementation, the beacons in the uplink schemeare further enabled to transmit other useful information associated withthe service use, such as the transmitter and beacon GPS co-ordinates,azimuth, used frequencies, transmitter power, antenna parameters, systemparameters, etc. In an exemplary embodiment, transmission by the beaconincludes only the unique beacon ID to minimize the information contentof the transmission, and the hence associated bandwidth, and to extendthe range for subsequent beacon detection through optimum signalformatting. Thus, each user of the Lower 6 GHz spectrum incorporates adata connection (e.g., first data link 1024, second data link 1026,reporting link 1030) to a database of the central server (e.g., centralserver 1004) to register operating parameters, and other key parametersin real-time, for use of the Lower 6 GHz spectrum by the respectiveuser.

As illustrated in FIG. 10, central server 1004 is similar to centralserver 412, FIG. 4, and central server 510, FIG. 5, in that centralserver 1004 represents a new form of SAS system. Central server 1004therefore provides yet a further improvement over conventional SASsystems that have been developed to introduce greater flexibility ofspectrum sharing. Although some conventional SAS systems havehistorically included capability for scalability, the present systemsand methods achieve significantly greater scalability potential throughuse of the improved and simplified propagation model described above.

In operation, central server 1004 performs database registrationsimilarly to the processes described above for the downlink embodiments.The database registration of central server 1004 includes all of theoperating system parameters, including the beacon ID, the transmitterGPS co-ordinates, azimuth, frequencies of use, transmitter power, andother key operating requirements. In some embodiments, the beacon isseparate from the transmitter. For example, a farm of satellite uplinksmay utilize a single beacon transmitter to transmit all such informationtogether, or as a series of IDs. The registered operating parameters ofeach beacon are relevant to the system operating parameters, and arethus sufficient to calculate potential interference. In an exemplaryembodiment, after a user (or AP) is registered in the database (notseparately shown in FIG. 10) of central server 1004, only the beacon IDis subsequently transmitted, since all subsequent detections of thebeacon transmission will enable central server 1004 to perform a lookupwithin its database for the ID of the detected beacon to determine otheruseful information required for subsequent control within the closedloop of system 1000. That is, the beacon operating parameters areprovided at the time of registration, and do not need to be subsequentlytransmitted to beacon detectors. Subsequent changes to the beaconoperation need only be sent to central server 1004 as a singleregistration update.

In an embodiment, the number range associated with the beacon ID isconfigured to transmit sufficient bits of information to uniquelyidentify a user. For example, if a 16-bit word is used for the beaconID, as many as 65,536 users may be supported. At present, this exemplarybit structure is more than sufficient to address the number of presentFSS and FS users, which is approximately 1,500 and 27,000, respectively,as demonstrated above. As the number of FSS and FS users increase, thepresent systems and methods may be further advantageously scaled toaccommodate such increases without system redesign. In one example, theword range of the beacon may be further reduced, but while supporting aneven higher number of users. That is, ID numbers may be reused for whereboth users of the same ID are geographically separated from each other.Because both FS and FSS use confined transmitter radiation beams, theknown geographic separation may significantly reduce ID word size. Thepresent inventors contemplate that, given that the number of main FSusers is 27,000 at present, this number reuse technique will enable areduction of a 16-bit word to less than 12 bits, with a reuse factor of16.

In practice, the beacon detection systems are installed at the locationof each spectrum users, e.g., at the receiver site thereof, to detectpotential interference to the user's service. In the exemplaryembodiment, beacon detectors are installed at each FS receiver, whichare much more sensitive to FSS transmitter interference than are the FStransmitters. Although the present embodiments are thereforeparticularly advantageous for FS users, the FSS beacon detectorsnevertheless also provide further significant benefits to the overallsystem, namely, the measurement-based propagation techniques, which maybe implemented at relatively low marginal costs in comparison withconventional techniques. The overall cost savings are even greater whenimplementing the uplink protection techniques together with the downlinkprotection techniques, described above, since both embodimentssubstantially utilize the same system beacon transmitter/detectorinfrastructure overlay and functionality.

In further operation of system 1000, the system detection sensitivity issufficiently high such that, in normal use, potential interferers areidentified well below the system noise floor before actually causing anyinterference. In practice, during the initial planning phase for theintroduction of a new radio AP or FS, the operating parameters of theradio AP/FS are determined in advance to avoid any potentialinterference from the FSS, based on dynamic knowledge of the FSSoperating parameters and the use of the MBP for greater accuracy.Similarly, for point-to-point microwave FS implementations, system 1000further advantageously enables planning for new a FS use in such amanner that an existing FS will not cause interference to the new FS.

Accordingly, the further implementation of the present auxiliary beacontransmission and detection systems onto the newly-introduced radio AP/FSprovides distinct advantages over conventional techniques. First, thepresent systems and methods provide a failsafe in the case of anunforeseen event; the real-time detection of the beacon may be used tocontrol the operating parameters of the FS users. Second, the presentsystems and methods provide a real-time measurement based propagation(MBP) system that enables accurate pre-planning of the initial operatingparameters open FS user to effectively avoid potential interferencebefore the interference occurs. In combination, both of these distinctadvantages form a closed loop system that advantageously enables thedynamically adjustable planning, monitoring, and control of interferencein real-time. Furthermore, operation of the present central serverimproves Wi-Fi service by assigning non-interference channels toadjacent Wi-Fi APs, and point-to-point FS systems may be planned inadvance to avoid interference from existing operations.

According to the advantageous principles herein, shared use of the Lower6 GHz band may be further extended for future Wi-Fi, as well as otherradio APs and satellite uplinks. The Lower 6 GHz band is ideally suitedfor such spectrum extension for Wi-Fi use. The Lower 6 GHz band is closeto the spectrum that the FCC has designated for U-NII use. The presentembodiments thus avoid the problems identified by the NTIA, above, andfurther, overcome the NTIA conclusion that there is no viable solutionfor U-NII devices to share the 5.35-5.47 GHz band with incumbent federalsystems. The present systems and methods provide an innovative technicalsolution in the downlink for FSS/FS systems that allow each system toeconomically share the central infrastructure.

In the exemplary embodiment, each radio AP, such as a Wi-Fi AP,innovatively transmits a radio beacon in its guard band or co-channelwhich uniquely identifies the beacon transmitter. As described herein,the present embodiments distinguish between radio/Wi-Fi APs, on the onehand, and FS devices, on the other hand, as different devices. Asdescribed above, unlicensed devices, such as U-NII equipment operatingunder the Part 15 rules, achieve significantly lower EIRPs, and maytherefore be managed differently from other devices, according to suchfactors as indoor/outdoor use, and/or individual and collectiveoperating power. Another significant difference is, for FS, the Azimuthmay be obtained during this coordination. However, in the case of smallcells, the small cells are either omnidirectional, or else it is hard toobtain their respective Azimuths. However, according to the presentsystems and methods, the respective small cells may include beaconsattached thereto, and the respective beacons may be detected at both theFS and FSS sites and the collected measurements passed thru to thecentral server.

In at least one embodiment, as described above, the interference fromsuch small cell devices may be further reduced in the case where thesmall cell devices are mandated only for indoor use only. Although suchmandates would be difficult to enforce, the known shielding effect ofwalls and metallized glass windows significantly reduces the potentialfor external interference on or from the small cell transmission. In anembodiment, system 1000 may be further configured to detect the presenceof a small cell device operating outside of its mandated use.

To support a much large user group, the number space (word length)allocated to the beacon is accordingly increased as well. Where the samebeacon frequencies are used, a contrast may be seen between theapproximately 27,000 present microwave point-to-point links, against themillions of Wi-Fi access points presently available. Nevertheless, asdescribed above, the number range of the IDs associated with these Wi-FiAPs may be significantly reduced by the present number reuse techniques.

In at least one embodiment, the systems and methods here further utilizetwo different beacon frequencies/frequency ranges: (i) one for FSmicrowave users, which is likely to require a significantly fasterresponse time for any unforeseen interference; and (ii) another for theWi-Fi radio APs, where a primary form of interference may be associatedwith an increase in the noise floor of the system, which in turn reducesthe system capacity, and thus results in a much slower response time topotential interference. Accordingly, these different number ranges maysupport the enhanced link budget performance of the entire beaconsystem. Alternatively, if the link budget of the beacon detection systemis increased to account for the relatively high propagation loss at theLower 6 GHz band in comparison with the 4 GHz band, then a single beaconfrequency may be implemented with an expanded beacon ID number range. Inone embodiment, an indoor-only Wi-Fi AP may not employ its own beacon,as the cost of implementation may be greater than the risk ofinterference in comparison with an outdoor AP.

Referring back to FIG. 10 and system 1000, advantageous fixed networkdata communication techniques are achieved, which avoid potentialinterference into the FS from satellite uplinks (e.g., FSS sites), andfrom Wi-Fi APs. In both instances, the present systems and methods equipthe satellite uplinks, the FS, and the Wi-Fi APs with beacontransmitters. The associated beacon receivers according to system 1000will be, in the exemplary embodiment, geographically distributed.

The downlink implementation of system 1000 retains many of theinnovative techniques of the uplink system 500 and associated protectionscheme 400, as well as a substantial portion of the same hardware, andtherefore the implementation of both of the downlink and uplink schemestogether realizes significantly greater cost advantages. In anembodiment of system 1000, the beacon receiver may utilize one ofseveral multi-antenna technologies, such as MIMO, to improve receivingdiversity and sensitivity. Given the concentration of microwave links inpopulated areas, and the number of existing microwave point-to-pointlinks to be approximately greater than 27,000, the present techniquesare highly effective at measuring virtually all potential interferencesources alone. In additional, the approximately 4,700-10,000 FSS in the4 GHz band would also include beacon detectors. Many of these will haveco-located the 4 GHz uplinks while separate Lower 6 GHz would also havebeacon detectors.

For example, in the case of a single beacon detector at a givenlocation, a steerable antenna may be utilized similar to that used withMIMO technologies, in order to detect beacons from different directions.Thus, each satellite dish located on a particular site can be pointed ina different direction, and this ability to steer the antennaadvantageously enables a more accurate measurement of the effect on eachseparate dish.

In combination, the novel and improved beacon sensor network overlaycould, at present, include as many as 30,000-40,000 sites in populatedareas of the United States, with an equivalent cellular coverage ofapproximately hundreds of meters of radius. In an exemplary embodiment,the link budget of system 1000 is approximately 200 dB or greater,thereby enabling system 1000 to adequately measure interferencesignificantly below the system noise floor. The present embodiments thusfurther improve over conventional schemes that realize link budgetsgreater than 200 dB because, as described herein, once a device isregistered (including its operating parameters), only the beacon IDneeds to be transmitted periodically to monitor environment changeswhich would affect interference propagation. In the exemplaryembodiment, other changes to the operation of a user or AP would beinstigated by the central server and directly recorded within itsdatabase, and would not need to be communicated to by the user or APitself. The present embodiments are therefore particularly useful withrespect to multiple access schemes developed for IoT, and may furtherimplement Zadoff-Chu functions used in LTE, or Weak Signal John Taylor(WSJT) used in amateur radio communications.

The central server according to the present techniques thereforerepresents a new and improved form of a Spectrum Access Sharing System,which represents a key innovative component in the present closed loopsystem that plans, monitors and controls interference dynamically. Thisdynamic control is best illustrated according to the followingadvantageous examples of implementing the present systems and methods.

(1) In the initial planning phase for the introduction of a new radio APor FS, the central server can supply operating parameters on grant forsuch successful introduction, because the central server has dynamicknowledge of the operating parameters of the FSS and other existing FSuse. At present, FS usage requires study prior to grant. According tothe present systems and methods though, the FS grant may automatic fromthe central server. As described above, the central server mayoptionally utilize conventional propagation models and optimizationtheory as a starting point, but automatically grant the new FS use basedon the additional dynamic knowledge provided by the new beaconinfrastructure overlay. The present systems and methods are able toadvantageously consider the influence of neighboring APs sharing theband, and then calculate aggregation to the system noise floor, as wellas direct interference.

(2) With knowledge of the transmitter powers, their EIRPs, and theirlocation, together with the measurements from the beacon detectors, thepresent central server is able to more reliably build accuratepropagation maps, with real-time measurements. Such real-time dynamiccalculations thereby avoid the problems experienced through use ofconventional propagation tools, which are intrinsically inaccuratebecause they necessarily require highly conservative assumptions toprotect the most sensitive users in the model.

(3) Once the operating parameters of a user/AP have been established andregistered, the central server is able to verify an optimal solution foreach system element using only the received beacon transmissions (andsubsequent real-time detections, such as by other beacon detectors inthe vicinity), and the real-time measurements thereof, to accuratelycalculate the propagation model). The central server may reliably thenconfirm the propagation loss, and only then authorize the particularoperation.

(4) Once the initial settings have been confirmed, then the centralserver monitors the specific interference, as well as the sourcethereof, to look for any changes in the environment which wouldnecessitate changes in real-time. Most of the changes detected would bebelow a performance threshold, thereby allowing small infrequentchanges. In some embodiments, such changes may be localized to a smallarea to avoid global changes (e.g., using optimizationgoals/optimization theory, and/or by using a pool of reservedfrequencies in that local area). However, should a strong interferenceoccur, then the detection of the associated beacon would allow rapidremedial action.

The techniques and inventions described above introduce new in theinnovative systems and methods that enable a significantly expandedsystem for sharing access to the same spectrum, but described hereinwith respect to the designated 6 GHz band, both between an FSS and anFS, and also between radio access points and Wi-Fi access points. Allsuch embodiments form a closed loop system that has the capability toplan, monitor and control interference in a dynamic fashion, such thesystem will allow shared use of the spectrum amongst competing userssuch that the maximum commodity of the spectrum is achieved.

The principles of the systems and methods described herein may befurther adapted to: massive MIMO transmissions, utilizing beamforming atthe AP/mobile base station to reduce interference to satellite systemsin the downlink; beacon formatting and transmission schemes to allow forgradual power increases to the beacon; extending the effective detectionrange of an individual beacon beyond a 2.4-5 km limit for an individualsite, where a network of widely deployed beacons may be directly orindirectly reported back to a central server, and particularly acrosspopulated areas; include on-site geo-distributed antenna arrays toreduce inaccuracies caused by multipath transmissions; computer programsand models to further refine the collection of real-time empirical dataand more accurately manage spectrum sharing and re-use across a range oftransmission bands; and technology upgrades to AP devices to includetheir own beacon detectors to better systematically link with FSS sitesand other APs for more accurate path loss estimates and more secureprotection.

The advantageous closed-loop configuration of the present embodimentstherefore provides significant versatility in the implementation ofprotection schemes utilizing the disclosed beacon detection techniques.That is, interference is effectively eliminated irrespective of whethera spread spectrum is utilized, or a narrowband transmitter. Beacondetectors may be deployed as integral components of the satellite dish,or as separate antennas, but neither deployment will create interferenceto the satellite dish itself. The present techniques create aself-organizing and self-policing network of beacon detection componentsthat avoids the need for overprotective safety margins, while unlockingsignificant—and previously unavailable—portions of the transmit spectrumfor further usage, such as by mobile devices.

The present systems and methods are further advantageously applicable tonew and developing 5G technologies, and also for frequency ranges bothabove and below the spectral bands described herein by way of example.For example, the embodiments described above for microwavepoint-to-point link protection may be implemented along lines similar tothose described herein with respect to cm- and mm-Wave 5G frequencies.However, since 5G beam transmissions are steerable to the direction ofthe receiver (which can move), in an exemplary embodiment, the presentbeacon detector is configured such that the beacon detector is able toscan 360 degrees. In this example, each individual operator may beassigned different bands, and thus it is very important to monitor theadjacent channel interference. Where operators share the same spectrum,protection will more closely follow the microwave point-to-pointembodiment of FIG. 10.

The central server of the present embodiments may be, for example,implemented within the context of current CBRS band infrastructures, asdescribed above, where multiple SAS operators share information withregard to their registers users (e.g., APs) such that each SAS operatormay individually perform the calculations needed to preventinterference. According to this current model, all SAS servers areconsidered equal, and there is no master server. The present embodimentsthough, enable a master server to be optionally designated. The presentembodiments are further advantageously capable of realizing, in the caseof a single operator, the deployment of a plurality of central serversin a cloud architecture in order to improve calculation speed,scalability and residence. In the exemplary embodiment, a master serverfor the infrastructure is designated to maximize such improvements.

UE Interference Management and Spectral Frequency Reuse

In the embodiments described above, although some of the registered FSSsites in the 3.7-4.2 GHz band may not be in use, the total number ofthese registered sites is nevertheless likely to exceed the numberoperating within the 3.55-3.7 GHz spectrum by at least two orders ofmagnitude. As described above, the CBRS band is considered manageabledue to the relatively small number of FSS sites, whereas the 3.7-4.2 GHzband includes over 4700 registered FSS sites, and possibly as many ormore unregistered FSS sites.

Signal path loss to a specific point within a cell is determined inconsideration of a number of factors, including transmission,environment, and losses due to multiple signal paths (multipath) causingself-destructive interference. At locations within an FSS coverage areatransmission modeling may be utilized to predict the available powerfrom the antenna with respect to interference. As used herein,“coverage” refers to the geographic area around the FSS site whereinterference from terrestrial radio transmitters may cause interference.In general, the amount of power at the antenna output is a function ofthe amount of power provided to the antenna, as well as the antennaradio frequency radiation pattern. This power output and antenna gain issometimes referred to as Effective Radiated Power (ERP) or, ifreferenced to an Isotopic antenna, the Equivalent Isotropically RadiatedPower (EMI)), which is the product of transmitter power and the antennagain in a given direction relative to an isotropic antenna of a radiotransmitter, The EIRP is typically listed in dBi (decibels overisotropic), and enables the conventional determination of signalstrength along various radials from the antenna. Other conventionaltechniques are known for calculating the ideal transmission lossutilizing transmitter power output, transmission cable loss, antennagain, free space propagation loss, and antenna and receiver gain.However, such conventional techniques are only able to predict atheoretical, best case scenario for coverage.

Another conventional technique is known as environment modeling, whichis used to determine the effect of terrain features between the cellsite and a specific position within the cell. In conventional parlance,the term “environment” refers to these terrain features, and not toactual weather conditions such as humidity, precipitation, temperature,etc. In general, the signal path losses attributable to dispersion willincrease as the inverse square of the distance from the cell siteincreases, however, environment factors can greatly affect these losses.Environment modeling considers the signal reduction due to the distancefrom an AP site, as well as diffraction losses caused by buildings orother terrain features between the cell site and the specific pointwithin the cell. Furthermore, since radio propagation conditions varysignificantly in typical operating environments, signal path loss modelsare known to account for the statistical variability of the receivedsignal (e.g., environmental shadowing) by incorporating suitable powermargins/offsets for the purpose of system planning. Nevertheless, asdescribed above with respect to FIG. 1, such conventional modelingtechniques still require highly conservative planning schemes that donot consider the actual conditions of the particular environment for thecell/AP site.

A third conventional modeling technique is used to predict the effectfrom multiple signal paths, and the resultant destructive interferencetherefrom, at the received location, i.e., multi-path fading. Multi-pathfading results from multiple paths taken by a signal from the cell siteto a specific point within a cell. Specifically, when two or more signalcomponents arrive at a particular reception point in space aftertraveling different distances, the received signals from these differentpaths may no longer be in phase. Accordingly, when these differentsignals are reunited, the difference in their respective phase shiftsmay combine in a destructive manner, and produce a degraded sum signalat the specific point of interest. Thus, it is not possible in practiceto achieve precision modeling of destructive interference because of thenumber of variables involved, their associated parameter accuracy, andthe relatively short (e.g., 7.1 to 8.3 cm) wavelengths used by the FSSservices (e.g., 3.6 to 4.2 GHz). Therefore, for system planningpurposes, conventional multi-path modeling techniques typically includepower margins/offsets in the path loss predictions to account for theeffects of multi-path fading, and such statistical modelling is highlydependent on the environment. Similar to the other conventional modelingtechniques, such margins/offsets typically require overly conservativepredictive values.

Furthermore, when determining the signal path loss from the FSS site toa specific point, where an AP may be placed, under one or more of theseconventional techniques, conventional signal path loss equations forcellular service communications must also be calibrated to accuratelymodel the specific area around the FSS site. However, because thespecific area around the FSS site might typically extend over tens ofkilometers for consideration of interference with placement of potentialinterfering antenna at clutter or below clutter, such calibration isparticularly challenging in practice and still require conservativeprotection margins. Conventional calibration techniques are known tocalculate values for geographical environment parameters, in order toaccount for such factors as urban, suburban, and/or rural morphology,height differences between the transmitter and the remote receiver, andthe density and height of terrain features between these two respectiveantennas. As described above, obtaining this information is expensive,and the information that is obtained is still subject to changeaccording to changes in the terrain (i.e., buildings built/demolished,trees leafing in the spring, shedding in the fall, etc.). Seasonalfoliage changes can have a significant impact upon signals in the3.6-4.2 GHz downlink frequency range.

Effective interference planning thus requires the use of suitable modelsto adequately predict interference, but the conventional modelsdescribed above are semi-deterministic or empirical, and therefore mustbe calibrated to the specific environments in which they areimplemented, which involves modifying the particular model parameters toapproximate the relevant measurement data. Some conventional propagationmodels include geographical parameters such as whether the environmentis rural or urban, the ground height relative to the transmitter, andthe terrain between the transmitter and receiver. In the conventionaltechniques, such environment information may be obtained from a sourcesuch as the Geographical Information System (GIS), but this informationis not obtained in real time.

Conventional modeling techniques also do not sufficiently consider theinterference effect from mobile UEs to the FSS site. Although anindividual UE may transmit an EIRP that is an order of magnitude lowerthan that of a fixed AP (see Table 2, below), the density of multipleUEs with in the area of interest may often be at least an order ofmagnitude greater than the density of APs within the same area, andtherefore the effect of multiple UEs may be as significant as, orgreater than, an individual AP, and the UEs are likely to be more evenlydistributed over the area than the APs. Moreover, because the UEs aremobile, and will often move locations around the terrain, the resultantinterference effects from the UEs may abruptly change, for example inthe case of a UE emerging from the shadowing effect of a building toobtain a direct line of sight to the FSS. Thus, the conventionalmodeling techniques described above, which are not based upon real-timemeasurements, are particularly limited in their ability to accuratelypredict interference to the FSS.

Through further development of the embodiments described above though,the real time measurement capabilities offered by the beacon-basedinfrastructure overcome these challenges presented by the conventionalmodeling techniques. The systems and methods described herein able toobtain (e.g., through implementation at the central server) a moreaccurate interference determination by first reasonably assuming thatparticular APs sharing the spectrum are at fixed points. Once thepropagation loss between an AP and the FSS site has been established(described above) the server is able to assume that this establishedpropagation loss of value is unlikely to rapidly change. However, insome instances, it may be impractical to utilize only the real-timebeacon transmissions to determine the UE effects due to suchconsiderations as (i) the considerable number of UEs that may be presentwithin a selected area, (ii) the variable range of speed at which themobile UE might be traveling (e.g., 0 km per hour (kph) for a stationaryUE, up to 130 kph for a UE traveling in an automobile on the highway),and (iii) variable shadowing effects as a UE comes within range oftaller or shorter buildings. That is, in some embodiments, beacontransmissions may be implemented at the UE level, in other embodiments,other parameters may be more practical to determine the UE effects onthe FSS site.

Table 2, below, lists the CBRS (i.e., 3.55-3.7 GHz) EIRP transmitterpowers according to device classification. As can be seen from Table 2,the EIRP of the typical UE device is considerably lower than the EIRPvalues of the several APs, namely, by an order of magnitude or more.Nevertheless, because the number of UEs that may be present within agiven area around the FSS site may be an order of magnitude or greaterthan that of the number of APs, the following embodiments implementtechniques for spectrum re-use and UE management around an FSS site.

TABLE 2 Device Classification dBm dBm/MHz AP - Category B: Rural 47 37AP - Non-Rural 40 30 AP - Category A 30 20 UE - End User 23 13

Spectrum Re-Use

FIG. 11A depicts an exemplary protection zone layering scheme 1100 foran FSS site 1102. FSS site 1102 is surrounded by a first area zone 1104,a second area zone 1106, and a third area zone 1108. First area zone1104 is smaller than, and encompassed entirely within, second area zone1106, and second area zone 1106 is smaller than, and encompassedentirely within, third area zone 1108. For purposes of this explanation,second area zone 1106 excludes first area zone 1104, and third area zone1108 excludes second area zone 1106 and first area zone 1104.

FIG. 11B illustrates a data table 1110 for calculating the respectiveparameters of area zones 1104, 1106, and 1108 according to scheme 1100,FIG. 11A. In the exemplary embodiment, data table 1110 is implemented tocalculate zones of spectral use, with satellite gain profile, for theseveral device classifications shown above in Table 2 distributedradially around the FSS. In some embodiments, calculations according todata table 1110 are further implemented for adjacent channels andco-channel interference. Data table 1110 depicts values for minimum linkbudgets, as well as safe responding distances, regarding examples of asingle interference source having the respective transmitter powersshown for the three different APs listed in Table 2. In the exemplaryembodiment, data table 1110 includes calculated values based onmeasurements regarding a propagation model for a residential morphology,having transmitter antennas deployed below clutter (e.g., 20 m), anddeveloped for 3.5 GHz. An AP operating in one of area zones 1104, 1106,1108, may be limited to an amount of allowable power and/or availablespectrum.

As illustrated in data table 1110, the calculated values assume amaximum interference value (e.g., noise input) of −129 dBm/MHz at thesatellite antenna waveguide for co-channel, and includes defined limitsfor the first adjacent channel and second adjacent channel. Asillustrated in FIG. 11B, higher limits for the first adjacent channeland the second adjacent channel take advantage of the out of bandemission limits of 40 and 52 dB, respectively. In the particularenvironment measured to obtain the exemplary values illustrated in datatable 1110, it is expected that higher safety distances would be yieldedover the −60 dBm aggregate LNB blocking limit. The calculationsillustrated in FIG. 11B are further shown with respect to the relativesatellite antenna elevation(s) to satellite(s) in geostationary orbit.From the exemplary values shown in data table 1110, it can be seen that,at a measured elevation of approximately 35 degrees, −6.6 dBi of antennagain is experienced from the terrestrial interference source. However,at 5 degree elevation, further north of this measurement location, theinterference source would experience 14.5 dBi of gain.

According to scheme 1100 and data table 1110, therefore, the link budgetfor co-channel may be calculated as being equal to −129 dBm/MHz(representing the maximum interference value) minus (i) the antenna gain(i.e., as a function of the elevation) and the transmitter power (indBm/MHz). Accordingly, two effective regions around the satellite of FSSsite 1102 are provided, namely, within the main beam satellite, andoutside of the main beam.

In the first effective region, which is within the satellite main beam,the positive gain profile of the satellite antenna is typically narrow.For a typical large satellite dish of several meters diameter, the halfpower (−3 dB) beamwidth is less than 5 degrees. However, for ITUinterference analysis using a conservative approach, the gain profile isassumed to extend over +/−20 degrees, and this gain profile is definedaccording to: Gain (in dBi)=32−25*LOG10(in degrees) with 0 dBi at 20degrees angles around the center (e.g., not taking LNB filter intoaccount). This gain profile equation thus follows the envelope of thesatellite gain profile, which will have various peaks and troughs.Nevertheless, when implemented with respect to the dynamic closed loopthe embodiments described above, the actual gain of the satelliteobtained from real-time measurements may be used.

Data from data table 1110 is taken, for example, from an exemplary 3.5GHz transmitter value, and assuming Non-Rural, Cat B Rural, and Cat A(e.g., height-limited to 6 m) APs, and a maximum number of end-userdevices. Accordingly, the loss for residential below Clutter may be15.2+45*LogD, where D is less than 200. For values of D greater than200, the loss may be −53.9+75*LogD. In this example, external small celldeployment is assumed to be below Clutter. The data of data table 1110does not assume indoor use, for which the relevant safety margins wouldimprove. Additionally, the size of the exclusion area, away from thebore sight, may be dominated by −10 dBi, and calculations of LNB may bebased on a single source, and then distance-modified for an equivalenthundred transmitters.

Use of such real-time measurements will thus advantageously enable thepresent systems and methods to advantageously implement significantlynarrower gain profiles than what are typically assumed by conventionaltechniques. Data table 1110 thus provides safe distance values from theFSS site for an interferer, and for several types of frequency positionswith respect to the satellite channel and the satellite elevation.

In the second effective region, which is outside of the satellite mainbeam the gain is assumed to be −10 dBi. In the exemplary values shown indata table 1110, an elevation angle of 48 degrees corresponds to −10 dBgain, and thus a corresponding safe distance may be adequatelydetermined for the radius of this second effective region.

These two effective regions from the antenna around the satellite of FSSsite 1102 thus account for the respective “tear drop” shapes illustratedfor the respective interference zones represented by first, second, andthird area zones 1104, 1106, and 1108. The present systems and methodsadvantageously utilize these effective regions such that portions of theunused spectrum that are not used by FSS 1102 may be used by APs thatare relatively close to FSS site 1102 in distance.

In the exemplary embodiment illustrated in FIG. 11A, the “round” portionof first area zone 1104 has a radius of approximately 150 m. First areazone 1104 thus represents an exclusion zone within which an AP or UE maynot use any of the spectrum. First area zone 1104 may therefore belabeled as a “red zone.” Further to this example, the round portion ofsecond area zone 1106 has a radius of approximately 300 m. Second areazone 1106 thus represents a “yellow zone,” within which an AP mayutilize 288 MHz of the available 500 MHz of spectrum, and for APtransmitter powers of 1 W (e.g., 30 dBm). Similarly, the round portionof the third area zone 1108 has a radius of approximately 750 m, andthird area zone 1108 thus represents a “green zone,” within which an APmay utilize the whole of the spectrum, and for AP transmitter powers ofup to 4 W. Outside of the green zone/third area zone 1108, the same fullspectrum is available for an AP, and for AP transmitter powers of up to50 W. The exemplary embodiment illustrated in FIG. 11A is depicted forthe use case two different channels. Other frequency utilization mayyield different frequency availability.

In the example illustrated in FIG. 11A, these exemplary values werecalculated under particular conditions. In actual practice of the thesetechniques, the central server may be configured to determine the actualpower, spectrum, etc. and dynamically adjust such operating parameter toreflect changes to the utilization of the spectrum, the arrangement ornumber of APs (and also their associated UEs, or other significantchanges to the environment.

The determination of these areas is calculated by the central server(SAS). They would be dynamic. For example, the available spectrumoutside the red zone would be a function of the utilization of channelsby the FSS. As it uses more channels less is available in yellow zone.Also, should the propagation environment change then the size of thezones can be re-calculated. This would influence the handover zonescoordinated by the central server and the EPC. If interference wasdetected, then the safety zones could be increased.

As demonstrated from scheme 1100, and according to the exemplary valuesin data table 1110, the effective operating distances for an AP near FSSsite 1102 are considerably closer to FSS site 102 than what isconventionally allowable, or possible, today (e.g., at present, theco-ordination distance for radio planning any potential shared use is150 km). The amount of spectrum that may be re-used, and the safeoperating distances thereof, are greatly improved according to theseadvantageous techniques, as well as the closed loop system of theembodiments described above.

Management of UE Interference

The advantages realized from the present embodiments are even furtherincreased by the effective management of interference from the UEs. Thepresent systems and methods further includes techniques to modify theeffective transmitter EIRP to represent its own AP EIRP, as well as thesum of all of the individual UE transmitter powers associated with theparticular AP, for interference calculations to adequately represent theeffect of UE interference. In this example, the power of the UE isconsidered as a function of the multiple access scheme of the UE, whichhas a maximum EIRP value of 23 dB in CBRS.

Thus, in the exemplary embodiment, the effective transmitter EIRPresembles a single point for the interference calculation, with thesingle point representing the AP and its corresponding UE community.This “single point” assumption it is justifiably accurate for theapproach of this exemplary embodiment, because the cellular coveragearea radius of the AP is relatively small in comparison with the muchgreater distance of the AP to the FSS site, and because this approachscales with the power of the AP itself. Accordingly, higher power APswill be to be deployed at distances further from the FSS site. In thecase of a UE having an EIRP of 23 dBm, associated with an AP with atransmitter EIRP of 47 dBm, the potential interference is significantlymore dominated by the AP EIRP.

However, this likelihood compares the actual EIRP of the AP against theEIRP of a single UE. The present embodiments therefore further considerthe effective transmitter EIRP to additionally reflect, in real-time,the number of UEs associated with the particular AP according to theirmultiple access scheme type. In some embodiments, this number ofassociated UEs is obtained through the beacon transmission/measurementtechniques described above. In other embodiments, the number of UEs isobtained using a fixed line connection from the AP to the centralserver, thereby avoiding the need to transmit a beacon with suchinformation each time there is a change to the number of associated UEs,which might occur often for some APs.

In at least one embodiment, the central server is configured to protectthe FSS site by assuming a predetermined, or pre-loaded, number of UEdevices associated with each class of AP. In this example, thepre-loaded number of UE devices represents a loading for the effectivecoverage areas of the differing types of transmitter. For example, moreUEs may be associated with a Class B AP transmitter than might beassociated with a Class A AP transmitter. Accordingly, if the number ofUE devices actually associated with the AP is lower than the pre-loadedvalue, then no reporting of changes would be required from the AP. Insuch circumstances, the AP may be configured to only report theassociated UE number to the central server when the pre-loaded number isexceeded, thereby advantageously reducing and/or minimizing thesignaling across the system.

In some instances, the variance of UE power associated with a shadoweffect may be assumed to be relatively small in consideration of thesafety margins described above, such as in the case of APs located asignificant distance from the FSS. Nevertheless, in an exemplaryembodiment, the central server is further configured to provide anestimate from its particular propagation model to represent a maximumlikely value of the shadow effect. This maximum likely value is ofparticular utility with respect to APs near FSS site 1102 in the yellowzone/second area zone 1106 outside of first area zone 1104 (theexclusion zone/red zone). Similarly, the central server may also beconfigured to estimate any significant multipath effects from theunderlying propagation model, that is, which has been self-calibrated byregistration of the respective beacons according to the systems andmethods described above. Accordingly, in the case where shared use ofthe selected spectral band permits carrier aggregation with the CBRSband, the present systems and methods will further advantageously enabledevelopment of APs that support the whole of the aggregated band.

FIG. 12 is a schematic illustration of a shared use system 1200 withinthe exclusion zone (i.e., first area zone 1104) around FSS site 1102,FIG. 11A. In the exemplary embodiment, system 1200 includes a centralserver 1202 (e.g., an SAS), a plurality of beacon-equipped APs 1204,with each AP 1204 having associated there with one or more UEs 1206. Inthe exemplary embodiment, system 1200 further includes a mobile corenetwork 1208, which may represent an Evolved Packet Core (EPC) of a LongTerm Evolution (LTE) network.

In exemplary operation of system 1200, contiguous service to the UEs1206 may be provided even within the satellite exclusion zone of firstarea zone 1104 through implementation of a handover 1210 to one of theumbrella CBRS bands, or alternatively, another one of the mobilespectrum bands under the control of core network 1208. If, for example,a portion of the C-band is re-allocated for mobile use (e.g., the lower200 MHz), while the remaining portion (e.g., upper 300 MHz) is retainedfor satellite use, the coexistence systems and methods described hereinare fully applicable to enabling a handover to this re-allocatedspectral portion where interference is detected. The principles of thepresent embodiments though, are not limited to this specificre-allocation case, or the particular spectral division even within thisexemplary case. In the exemplary embodiment, handover 1210 isaccomplished through utilization of a link 1212 between central server1202 and core network 1208. In one example, handover 1210 may betriggered when a particular UE 1206(2), associated with AP 1204(2),comes within a defined distance from FSS site 1102. Further to thisexample, outside of the exclusion zone of first area zone 1104,association and use the given spectrum (e.g., C-band, etc.) may beimplemented when in range of a small cell.

According to an exemplary embodiment of system 1200, central server 1202may be further configured to permit no spectral band registration withinthe exclusion zone of the first area zone 1104 as the AP registrationprocess will include the geographical coordinates of the AP. Under thisembodiment, APs within the exclusion zone of a 3.7-4.2 satellite FSS maycover the whole 3.55-4.2 GHz spectrum, but only the 3.55-3.69 GHzspectrum would actually be available. In this example, the 10 MHz ofspectrum from 3.69-3.7 GHz is withheld from availability to represent aguard band. In the case where no guard band might be required, thisadditional 10 MHz might also be made available. In an alternativeembodiment, the macrocell of a Mobile Network Operator (MNO) isutilized.

According to the advantageous systems and methods described furtherherein, a more effective and accurate means is provided to represent theeffects of UE-based interference on an FSS site, and particularly withrespect to the particular spectral band and a UE associated with anindividual AP. Such representative means is distinguishable overconventional techniques, and that it reflects the actual number of UEsassociated with an AP in real-time, and further enables an accurateestimate of the statistical variation of the UE interference due toshadowing effects.

The present embodiments further advantageously enable the creation of astrict exclusion zone around an FSS site for protection, while stillallowing UE use of CBRS and macro-cellular spectrum within the exclusionzone. The present embodiments further provide a series of zones outsideof the exclusion zone (two such additional zones described herein, butmore could be realized within the scope of this disclosure), whichincreasing allow the use of the band spectrum at greater distances, andfor higher transmitter powers. According to the exemplary principlesdescribed herein, contiguous UE service across is realized within thevicinity of an FSS site, and up to the location of the FSS site itselfthrough use of a handover (e.g., with an EPC). This handover is furtherenabled by providing a new communications link between the EPC in thecentral server. The dynamic nature of these zones thus reflects thechanges in FSS channel utilization, as well as changes in theenvironment.

The central server according to the present embodiments may be furtheradvantageously configured to enable the combination of the CBRS spectrum(3.55-3.7 GHz) and the C-band spectrum (3.7-4.2 GHz), etc., within anAP, as well as the development of APs that more effectively utilize thiscombined spectrum. The central server may be further configured toprevent AP registration within the exclusion zone, while additionallybeing able to obtain the location of a given AP based on broadcast orhard link signal of a GPS location, or according to the other beacontransmission/detection techniques described above.

UE Beacons

As described above, the beacon infrastructure and techniques of thepresent embodiments are applicable to UEs, in addition to APs. Although,due to the vast number of UEs operating throughout the country, as wellas the additional cost involved in extending the beacon infrastructureto the UEs and the related reduction in transmitter power thateffectively reduces the link budget (and thus the system detectionrange), it might not always be practical to extend the infrastructure toall UEs.

Nevertheless, it is useful to enable the UEs to emit their owntransmitter beacon in the case where the relevant AP or APs is/are closein proximity to the FSS site where the variance of the effects of the UEtransmitter power would be more difficult to model or require overlyconservatively protection limits. In an exemplary embodiment, a UEbeacon may be provided using a client on the UE device or within itsoperating system, which is instructed to operate according to thecentral server. It may be assumed that such devices are close inproximity to the FSS site, however, the issue of limited link budgetwould not be a significant concern because the close-proximity of UEdevices and also because this number may be considered to be relativelysmall.

Additionally, the use of UE beacons may be advantageously limited to beperformed only, for example, during a training or calibration phase, andnot as a continuous operation. That is, in this example, during aninitial calibration phase, the UE beacons associated with a particularAP may be measured at different locations around the AP with which theyare associated. These UE beacon measurements, together with themeasurement of the AP beacon, may then be used to determine theeffective AP transmitter power and its statistical distribution torepresent the whole interference effect as a single point as function ofthe number of UEs, namely, the effective EIRP of the AP. Over time,central server may be configured to develop a detailed statistical modelfor the AP and the number of UEs associated there with. This statisticalmodel may then be used to determine the safe transmitter power of APs inclose proximity to the FSS site, for example, up to 500 m.

The central server may be further configured to dynamically reduce theallowed transmitter power of the AP by taking into account the shadowingeffects of buildings within the area experienced by UEs. By accountingfor the shadowing effects, the operation of the system is furtherenabled to directly reduce the AP interference, while also reducing thesize of the coverage area of the AP, and thus the number of UEs thatwill likely be supported by the AP. In some instances, the centralserver may be configured to subtract the shadow effect of buildings onthe edges of a particular area where the relevant UEs good instead besupported by a CBRS or macrocell, thereby rendering the total effect ofthe APs and associated UEs significantly more deterministic.

FIG. 12A is a schematic illustration of shared use system 1200, FIG. 12,with respect to all three area zones (i.e., first area zone 1104, secondarea zone 1106, and third area zone 1108) around FSS site 1102, FIG.11A. In this exemplary embodiment, system 1200 further includes at leastone beacon detector 1214 within exclusion zone 1104, which has a fixedconnection 1216 to central server 1202. In this exemplary embodiment,respective UEs 1206 include a UE beacon transmitter 1218, andmeasurement of the beacons transmitted from one or more beacontransmitters 1218 is performed by beacon detector 1214. The datameasured from the received beacons may be then relayed to central server1202 over fixed connection 1216. In other embodiments, a wireless linkmay be used where a fixed link is not available.

FIG. 12A thus illustrates a multi-zone operational distribution of UEs1206 around FSS site 1102. In the exemplary embodiment, central server1202 manages potential interference by preventing any of UEs 1206 or APs1204 from broadcasting within innermost exclusion zone 1104 (red zone).In further operation the exemplary embodiment, system 1200 permits UEs1206 within second area zone 1106 (i.e., UEs 1204(1), 1204(2), 1204(4),1204(5) in the yellow zone), exploitation of the available spectrum, atreduced transmitter power(s). Outside of second area zone 1106, withinthird area zone 1108 (green zone), central server 1202 is configured toallow further spectrum availability, and at higher transmitter powers(e.g., UE 1206(6)). High propagation loss over distance from FSS site1102 thus contributes to the additional spectrum availability and highertransmitter power in third area zone 1108. Beyond third area zone 1108,UEs 1206 operate in a conventional fashion (e.g., UE 1206(7)).

The examples described above are discussed with respect to UEs atdistances of less than approximately 500 m from the FSS site. In theexemplary embodiment, at distances greater than 500 m, the effect of UEs1206 may be alternatively modeled using the effective EIRP, whichrepresents the AP transmitter power, and also considers the additionaleffect of the number and type of UEs associated with the particular AP.Under 500 m, such modeling techniques would not be expected to be asaccurate due to the difficulty in modeling the effect of UEs 1206 as asingle point source of interference coincident with the AP position dueto the propagation variation associated with UE movement. Thus, insystem 1200, UEs 1206 are configured to transmit a beacon fromrespective UE beacon transmitters 1218, when instructed by centralserver 1202, such that beacon detector 1214 is able to detect thetransmitted beacon by measuring the received power against the positionof the UE 1206 transmitting the beacon.

In an alternative embodiment, an exclusion zone of 500 m around the FSSis created, and in which central server 1202 permits no UE to operateusing the 3.7-4.2 GHz spectrum. At distances of 500 m and greater, theUE may then be permitted to operate using the effective AP power. Thisalternative may be useful in the case where the system might moreoptimally determine that risk of interference is outweighed by theoperational cost (e.g., power, computational requirements, etc.) ofhaving the UEs transmit their on beacons, and the associated modelingcomputations that arise therefrom.

Similar to the embodiments described above, in the exemplary embodiment,the transmitted beacon includes the ID of the particular UE 1206, itstransmitted power, and its GPS location/position. Through suchmeasurements, central server 1202 is able to collect detailedmeasurements of the plurality of UEs 1206 associated with respective APs1204, and dynamically model the interference management therefrom. Insome embodiments, beacon detector 1214 is alternatively, oradditionally, in communication with central server 1202 over acommunication link other than fixed connection 1216.

The interactive functionality of central server 1202 with EPC 1208 thusenables handovers 1210(1), 1210(2), 1210(3) from the associated spectrum(e.g., including the C-band), to either the CBRS or mobile networkmacrocells. Accordingly, any interference to FSS site 1102 from UEs 1206may be avoided by locating the UE broadcast within other spectrum bandsor C-band guard bands. In an embodiment, central server 1202 isconfigured to initiate and sequence the beacon transmission from bothAPs 1204 and respective associated UEs 1206. According to this exemplarymultiple access scheme, the signaling load on system 1200, as well asthe computational load on central server 1202, is significantly reduced,and conflicts are further advantageously avoided.

Through the collection of measured beacon transmissions from the severalUE beacon transmitters 1218, a detailed coverage map of one or more APs1204 may be built, dynamically and in real-time. Dynamically becausethese models can be updated from time to time to take into effect anyenvironmental changes. This coverage map thus represents an effectivemeans of representing the AP transmitter power, with an effective EIRPthat reflects a sum of the individual respective UE transmitter powersassociated with that AP 1204, as well as the type of individual UE 1206,and the associated variance of different UE positions. In an exemplaryembodiment, central server 1202 is further configured to calculate astatistical distribution of respective UEs 1206, and utilize thisstatistical distribution within an optimization algorithm for protectionof FSS site 1102.

FIG. 12B is an overhead view of a partial schematic illustration of acorner effect 1220. In the exemplary embodiment illustrated in FIG. 12B,corner effect 1220 is depicted with respect to a presence of thebuildings 1222 disposed between one or more UEs 1206, FIG. 12-12A, andFSS site 1102. In this example, building 1222 is disposed along a firstdirect path 1224 between UE 1206 and FSS site 1102 at an initialposition of UE 1206. As UE 1206 moves in a direction 1226, a seconddirect path 1228, between UE 1206′ and FSS site 1102, is unblocked bybuildings 1222. That is, movement of the UE 1206, from “behind” building1222, and into a direct line of sight as UE 1206′, can lead to adramatic increase in the potential interference to FSS site 1102 when UE1206′ is in close proximity to FSS site 1102, in comparison with UE 1206behind building 1222.

FIG. 12C is a partial schematic illustration of a hotspot effect 1230.In the exemplary embodiment illustrated in FIG. 12C, hotspot effect 1230is depicted with respect to handover 1210 in the vicinity of a hotspot1232, and with respect to first area zone 1104 and second area zone1106. More specifically, where there is unacceptably high signalstrength from a particular UE 1206 to FSS site 1102, i.e., at beacondetector 1214, central server 1202 may be configured to coordinate withEPC 1208 to cause handover 1210. This region of unacceptably high signalstrength thus creates hotspot 1232. In the exemplary embodiment, centralserver 1202 is further configured to identify such hotspots 1232 ofpotential interference during an initial calibration phase. In the casewhere hotspots 1232 identified during initial calibration, hotspotidentification need not be a continual or ongoing operation of centralserver 1202. In some embodiments, central server 1202 may be configuredto perform hotspot identification periodically, continually, or uponmeasurement of an environmental change. According to this advantageousembodiment, central server 1202 is further able to managing potentialinterference by directing APs 1204 or UEs 1206 to avoid hotspots 1232.

Similar to the embodiments described above, in the examples depicted inFIGS. 12-12C, the resulting propagation loss and lower UE transmitterpowers may be considered to have a negligible effect outside ofdistances approximately 500 m away from FSS site 1102. The 500 mthreshold in this example though, is discussed by way of example, andnot in a limiting manner. As described above, transmitter power and therespective radii of area zones 1104, 1106, 1108 may vary. However,according to the several embodiments depicted in FIGS. 12-12C, centralserver 1202 is able to dynamically adjust the size of the respectivearea zones according to the dynamic measurements that are collected inreal-time. System 1200 is thus able to further consider the relativedistances and powers of APs 1204 from FSS site 1102. That is, asrelatively high-power APs 1204 are located distances far from FSS site1102, the contribution of UEs 1206 associated with that high-power AP1204 is considered to be relatively small in comparison to the muchstronger AP power.

Self-Calibrating Propagation Models

Several conventional techniques utilize empirical propagation models todetermine FSS interference from other APs and mobile UEs for sharedspectrum use and/or realization of the maximum commodity of thespectrum. One such conventional technique simulates wireless informationtransport systems using time and frequency dynamic effects on stationaryand mobile systems. The technique employs several modules in adistributed interactive simulation structure to provide a real-timesimulation output signal that is adjusted by voice and data inputs.Another conventional technique utilizes a computer implemented modelingtool for cellular systems that predicts signal strength in considerationof terrain effects and the presence of man-made structures. Thisconventional technique predictively models under the line of sightconditions, similar to the highly conservative propagation toolsdescribed above with respect to FIG. 1.

A third conventional technique performs interference studies in atwo-step process, which first analyzes all potentially interferingsystems to exclude systems that can be determined to not be causinginterference, and second, performs a more detailed analysis on theremaining systems that cannot be excluded in the first step. Thistechnique utilizes pre-calculated average terrain and roughness values,and substitutes an effective antenna height for the actual antennaheight in its propagation loss calculations. A fourth conventionaltechnique models radio field strength for cellular site coverage byautomating sampling procedures, collecting data at various monitoringpoints, and interpolating the collected samples/data. An iterativeapproach is used to mitigate calibration errors, but conventionaltechnique requires the introduction of noise into the data analysis toavoid convergence on a local minimum.

Accordingly, each of these conventional empirical propagation modelingtechniques produce significant inaccuracies from the assumptions thatare required in the respective model. Furthermore, calibration of theseconventional empirical tools is expensive, and also particularlychallenging for determining the interference to an FSS site from otherAPs/UEs for shared spectrum use. The following embodiments thereforefurther expand upon the innovative MBP model and beacon-based systemsand methods described above. More particularly, the embodimentsdescribed further herein provide a more accurate and inexpensiveself-calibrating propagation model is provided.

Referring back to FIG. 4, transmit frequencies and power levels may beauthorized for an AP based upon a measured path loss, or on acalculation of the loss between the AP and the FSS site. In bothinstances, a propagation model may be implemented to calculate therespective loss. The present embodiments therefore derive a propagationmodel that overcomes the weaknesses of the conventional empiricalpropagation models described above. The exemplary propagation modeldescribed herein avoids the inaccuracies associated with the empiricalmodels, and also the expense of calibrating the empirical models toachieve maximum commodity of the spectrum. The present propagation modelembodiments represent significant improvements over the conventionalmodels that are unable to determine from individual measurements thesignal strength at every point within the cell, such that cell coveragecan be confirmed, and problem locations can be identified and addressed.The improved modeling techniques herein allow cellular serviceproviders, for example, to more optimally determine an initial cell sitelocation, the optimum placement of additional cell sites, frequencyplanning, and required power levels at specific sites.

In the exemplary embodiment, modeling of the environment furtherconsiders the reduction of the signal caused by the distance from a cellsite, as well as diffraction losses caused by buildings or other terrainfeatures between the cell site and the specific point within the cell.Such considerations are determined in real time from the MBP schemedescribed above, and therefore represent still further improvements overconventional techniques, which are unable to accurately track thevariance of radio propagation conditions that will inevitably occur inthe typical operating environment. As described above, conventionalsignal path loss models are only known to account for the statisticalvariability of the received signal (e.g., environmental shadowing) byincorporating suitable power margins/offset calculations for systemplanning purposes.

In an exemplary embodiment, a propagation modeling scheme utilizes radiobeacons to further implement MBP: (i) as part of the overall system thatprotects against/prevents interference to the FSS site from theintroduction and service of an AP/RAP sharing the same spectrum; and(ii) to develop a self-calibrating, “learning,” propagation model thatbecomes increasingly more accurate over time, such that the modelsubstantially reflects the actual dynamic environment conditions in thesystem. In the exemplary embodiment, such self-calibration capability isautomatic, and does not require (human) operator direction orintervention for cellular planning.

In some embodiments, utilization of the present propagation model maynot be considered to play a significant role with respect tointerference prevention. In other embodiments, as described above, thedynamic and closed loop nature of the propagation model is significantlyadvantageous to mitigate interference effects. Nevertheless, in eithercase, the exemplary propagation model described herein is particularlyadvantageous with regard to the planning of optimum coverage andcapacity in the design and evolution of APs for a service provider. Thepresent self-calibrating propagation model is further useful to identify“hot spot” regions of potential interference, which are conventionallyknown to be chaotic and unpredictable. The present propagation modelstill further is useful to identify areas where the multipath effect issignificant; the present model enables the central server to accuratelyestimate the multipath effect for interference migration.

The propagation model described herein further avoids the problemsencountered through implementation of the conventional empirical models,but without sacrificing some useful capabilities of the empiricalmodels. That is, the present propagation model is advantageouslyscalable, and may be configured to enable to include additional marginsbuilt into the system model to address potential interference that nightnot to be fully addressed by measurements only. For ease of explanation,the embodiments below are described with respect to one particularexample in which operation of the system is based on a requirement toachieve a beacon link budget of at least 200 dB (satellite elevation of5 degrees with a significant number of APs). Although different linkbudgets and other parameters are well within the scope of thisapplication, the examples below are illustrative to demonstrate thedetection of distance co-channel interference from multiple sources.Such multiple source detection may be achieved, for example, throughtransmission and detection of the unique ID of the AP (e.g., to minimizebandwidth usage, described above), or according to one or more complexdetection schemes designed with respect to IoT applications.

FIG. 13 is a schematic illustration of a shared use system 1300 thatimplements an MBP scheme for a self-calibrating propagation model. Inthe exemplary embodiment, system 1300 includes a central server 1302(e.g., an SAS) for managing interference to a plurality of FSS sites1304 (four such FSS sites shown in this example, 1304(A)-1304(D))). Inthis example, each FSS site 1304 operates within a respective terrainregion 1306, and each FSS site 1304 is equipped with at least onerespective beacon receiver 1308 in operable communication with centralserver 1302. A system 1300 further includes a plurality of beacontransmitter-equipped existing APs 1310 distributed among the pluralityof terrain regions 1306. As illustrated in FIG. 13, an individual one ofthe respective terrain regions 1306 may overlap with one or more otherterrain regions 1306.

In exemplary operation of system 1300, each of beacon receivers 1308records the signal strength of a beacon transmission detected from oneor more existing APs 1310, similar to the embodiments described above.In at least one embodiment of system 1300, one or more of beaconreceivers 1308 is further configured for direct connection to centralserver 1302, and dynamically informs central server 1302 of theoperating conditions (e.g., channel of operation, location, pointingdirection, etc.) of the respective FSS site 1304.

In further exemplary operation of system 1300, a beacontransmitter-equipped new AP 1312 is introduced and seeks transmitauthorization from central server 1302, similar to the operation ofsystem 500, FIG. 5. In this example, new AP 1312 is located within anoverlapping region 1314 that extends across portions of each of terrainregions 1306(A), 1306(B), and 1306(C). Introduction of new AP 1312 intosystem 1300 may, for example, be performed in a manner similar toprocess 600, FIG. 6, such that new AP 1312 may share the same C-bandspectrum, within overlapping region 1314, as FSS site 1304(A), FSS site1304(B), and FSS site 1304(C). In the exemplary embodiment, theself-calibrating propagation model of system 1300 is implemented bycentral server 1302 within step 606. Process 600 otherwise may beimplemented in a manner similar to that described above with respect toFIG. 6.

That is, central server 1302 of system 1300 is configured to implementstep 614 such that new AP 1312 AP transmits a beacon which is detectedby beacon receivers 1308(A), 1308(B), and 1308(C). In the exemplaryembodiment, the detection by the respective beacon receivers 1308 occurssubstantially simultaneously. Similar to the embodiments describedabove, the beacon transmitted by the beacon transmitter (not separatelyshown) of new AP 1312 includes the unique ID of that particulartransmitter and/or AP, as well as the transmit power of beacontransmitter itself. In some embodiments, the beacon transmitter isfurther configured to transmit location information (e.g., GPS dataand/or map data in x, y, z co-ordinates), as well as the number of UEsassociated with new AP 1312, over a fixed communication channel,wirelessly, or over the Internet.

In the exemplary embodiment, information other than the beacon ID istransmitted over the Internet to maximize efficiency, and therebyfurther enhance the link budget of system 1300 by reducing the overallinformation content between beacon transmitters and receivers. In atleast one embodiment, central server 1302 is further configured tomanage not only potential interference from new AP 1312 to all FSS sites1304 encompassing overlapping region 1314, but additionally potentialinterference by UEs (not shown in FIG. 13) associated with new AP 1312(as well as existing APs 1310, as needed) along with consideration ofthe measured path loss.

Central server 1302 may, for example, include an SAS, and may be furtherconfigured to calculate the respective three-path loss associated withthe three separate links (not separately shown) between new AP 1312 andFSS site 1304(A), FSS site 1304(B), and FSS site 1304(C), respectively,to determine if there is likely to be interference. In at least oneexemplary operation, FSS site 1304(D) is also able to detect the beacontransmitted by new AP 1312, thereby resulting in a four-path losscalculation. In this instance, central server 1302 of system 1300 isconfigured to calculate four propagation models, respectively,representing the four different terrain regions 1306 (in the exampleillustrated in FIG. 13) associated with each FSS site 1304. That is,central server 1302 manages the introduction of new AP 1312, and thepotential interference therefrom, according to the four differentmorphologies.

In one exemplary morphology of FSS site 1304(D), if the signal strengthof the beacon (i.e., transmitted by new AP 1312) received at beaconreceiver 1308(D) falls below the sensitivity of beacon receiver 1308(D),the beacon will not be successfully detected. In such cases, centralserver 1302 is configured to determine that new AP 1312 would not causeinterference two FSS site 1304(A). That is, although the beacon signalwould have fallen below the threshold for detection at 1308(D), thebeacon may still be detected by other APs, which will have reported suchbeacon detection to central server 1302. Therefore, central server 1302will still be able to verify that the beacon signal from AP 1312 wasoriginally transmitted.

In the embodiments described above, the self-calibrating propagationmodeling technique not only serves an important role in theauthorization process for subsequent transmissions by new AP 1312, thenew technique further provides valuable information pertaining to thecalibration of each of the four respective propagation models for eachpotential communication pathway. Although each of the four respectivepropagation models may be calculated in similar manner as with respectto one another, each model will involve different associated parameters.

Systems and methods according to the exemplary embodiment depicted inFIG. 13 further advantageously enable the real-time identification andremediation of potential interference. That is, although the primaryfunction of the beacons described above is to enable MBP, because eachpotential source of interference will have its own unique ID, centralserver 1302 is enabled to immediately identify and remedy theinterference by instructing the interfering AP to cease operation and/oruse a different frequency/transmit power, similar to the remediationsteps of process 600, FIG. 6. According to the improved configuration ofsystem 1300, such interference may be detected and remedied eitherduring the initial installation phase, or during subsequent operation.In the exemplary embodiment, beacons are periodically transmittedaccording to a schedule, such that the overall health of system 1300 maybe maintained even as changes occur to the system environment. In atleast one embodiment, central server 1302 performs regular measurementsand calculates statistical variations over short time periods, such thatfurther valuable multipath information is advantageously provided toenhance the overall interference protection by including a margin forthe statistical variation, separately from or in addition to specificparameter measurement values.

Similar to system 400, FIG. 4, system 1300 may also be configured suchthat individual beacon transmitters transmit to other transceivers(e.g., beacon detectors, central server, other beacon transmittershaving a receiver component) within range, and feed the signal strengthback to a centralized database of central server 1302, which therebysignificantly enables central server 1302 to train the propagation toolto be more effectively self-calibrating. In conventional systems,information is collected by physically driving automotive vehiclesequipped with signal measurement equipment and GPS technology along therespective signal paths to log into the measured values. According tothe improved techniques according to system 1300 though, central server1302 and beacon receivers 1308 are configured to automatically collectthe measurement information with each beacon transmission, since thelocation of each AP is considered to be fixed, and the respective beaconID is recorded upon registration, the new measurement information may berecorded without having to recalculate the AP, and by verifying thebeacon ID using a lookup within the database of central servers 1302.

Because, in the exemplary embodiment, the beacon transmissions aretransmitted regularly, the self-calibrating propagation model of system1300 is able to evolve over time, and thus rapidly represent the trueand accurate dynamic conditions in each terrain that occur in real time.

The dynamic self-calibrating features of the present embodiments furtherprovide the advantageous extension of the beacon infrastructure into aform of self-organizing protection (SOP). Specifically, apart from theprimary beacon function for MBP, the present embodiments further enablethe configuration of central server 1302 such that the introduction ofnew AP 1312, or its periodic beacon transmission, will serve toadditionally measure the transmission loss to existing APs 1310 to yieldfurther valuable information useful for network planning, such as FDMA,and for improving the underlying self-calibrating propagation model forthe whole area of the plurality of terrain region 1306. According tothis advantageous configuration, the MBP capabilities of the beaconinfrastructure described above are effectively extended to SOP. Whetherdirectly or indirectly implemented for FSS protection, the exemplaryembodiment of FIG. 13 nevertheless yields considerable informationuseful for the inexpensive calibration underlying self-calibratingpropagation model. In some embodiments, the beacon ID is transmittedover a dedicated signaling channel. In other embodiments, the beacon IDis transmitted over a guard band close to the channel of potentialoperation.

In a practical example, system 1300 may include thousands of existingAPs 1310. In such instances, the introduction of a new AP 1312, alongwith the announcement of the beacon/beacon ID associated there with,will yield potentially hundreds of measurement data points (or more) atother locations, and substantially at the same time as the correspondingmeasurements at the relatively fewer FSS sites 1304. According to thisexample, existing APs 1310 may be structurally configured to include anadditional radio receiver dedicated for beacon detection, which may bespecifically tuned to the relevant beacon signaling channel or guardband. This exemplary configuration further allows a main radio of thesystem (not shown), such as for an LTE network, to operate full-time oncommunication, with the secondary radio on full-time beacon detectionservice. Where only one radio receiver is included, an LTE network radiomight be disturbed if required to periodically go into a listeningmode/pre-planned listening mode. According to these advantageoustechniques, as the concentration of APs within one or more terrainregions could effectively converge the self-calibrating propagationmodel with the regular MBP functioning of central server 1302, since thetransmission loss vectors between the individual points in space willhave already been measured and continuously updated. In the case of thesystem reset, the evolving self-calibrating propagation model may berestarted and run until the concentration of APs increases to a level torender the propagation model unnecessary.

In an exemplary embodiment, central server 1302 is further configured toconsider the range of individual beacon transmissions. Referring back toFIG. 3A, for an azimuth of 0 degrees, a satellite dish elevation of 5degrees, and a satellite gain of 14.5 dB, the limit for co-channelinterference is 180.5 dB with a single interference source within thesatellite main beam. Accordingly, allowing for higher gain antennas andmultiple sources, it can be seen that a link budget of at least 200 dBwould be required for an elevated 5 degree FSS site. In some cases, linkbudgets of up to 240 dB are achievable. However, according to theadvantageous embodiments herein, it will not be necessary to requiresignificantly greater link budgets, since the amount of additionalinterference from this difference would be considered to be relativelysmall. Nevertheless, in at least one embodiment, central server 1302 maybe further configured to include a fixed penalty in its interferencecalculations to account for this relatively small increase ininterference.

The present systems and methods are further advantageously capable ofconsidering, within the self-calibrating propagation model, respectiveatmospheric effects encountered by the system, such as tropospherescatter, which may results in unpredictable long-range propagationbehavior. For purposes of this discussion, “atmospheric” is defineddifferently from “environmental,” as described above. Atmosphericeffects are not only highly unpredictable; such effects also tend to bevery short-lived. Conventional systems are thus incapable of determiningthe atmospheric effects on the system in real-time. According to thepresent systems and methods though, the MBP capabilities achieved fromthe beacon infrastructure is further useful to identify the source ofthe AP(s) subject to the atmospheric effects, and then control thepotential interference resulting from the affected AP(s).

In the conventional systems, the unpredictability of the potentialatmospheric effects is often cited as a reason for requiring such largeprotection zones around an FSS site. In practice, however, theprotection zone requirements are often because of the mobile use case,which involve sharing with macro-cells, which are designed to haveantennas above clutter, in order to provide longer range cellularcoverage. Nevertheless, such affects may migrated by the use of smallcells below clutter, which take advantage of the more hostilepropagation conditions. This migration though, effectively rules out theshared band use with the respective macro-cellular base stations, whichhave antenna heights above clutter, and hence suffer relatively lowpropagation losses to those antenna below clutter, as illustrated belowwith respect to FIG. 14 (as described further below, small cell use maybe realized within the scope of the present systems and methods).

FIG. 14 is a graphical illustration 1400 depicting comparative dataplots 1402 of single-slope and dual-slope models for high densitycommercial morphology-per-clutter classifications. In the exampleillustrated in FIG. 14, the path loss (vertical axis, in dB) is plottedagainst distance (horizontal axis, in meters) for both of thesingle-slope and dual-slope models, and for both model types belowclutter, at clutter, and above clutter. As illustrated in FIG. 14, thecomparative data plot 1402 are charted against a free space path lossplot 1404. In an exemplary embodiment, one or all of comparative dataplot 1402 and free space path loss plot 1404 are utilized within theself-calibrating propagation model described above.

According to the advantageous techniques described herein, small cellsmay therefore be deployed below clutter to share the same spectrum asthe FSS site using the relevant spectral band. The present embodimentsfurther provide the self-calibrating propagation model that uses abeacon infrastructure to more accurately measure the interferencecontribution from the one or more APs sharing the same band (e.g., theC-band) as the FSS site. This new propagation model further enables thecentral server capability to detect environmental changes, and thenincorporate those detected changes within its calculations todynamically protect the FSS sites.

The present systems and methods further enable the capability of theshared use system, using the unique IDs of the separate beacons, todetect both short and long-range interference. Using the MBP scheme ofsuch beacon detection, the system is further enabled, at the centralserver, to control the individual APs to mitigate the potentialinterference. The self-calibrating capabilities of the propagation modelfurther enables a significantly improved capability for the design andoptimization of AP coverage and capacity for mobile systems, as well asthe measurement of individual beacon signal strength to assess thepotential multipath effect, and thereby build in additional parameter orstatistical variation margins for still further interference protection.The same beacons may be used for self-organizing protection, and for alearning calibration model that automatically improves the accuracy ofthe propagation modeling over time. The present systems and methods areadditionally scalable, and may include two separate radios, with onesuch separate radio dedicated for beacon detection.

Increased Beacon Detection Range

Further to the beacon infrastructure embodiments described above, it isdesirable to increase the range for beacon detection, and particularlywithin the 3.55-4.2 GHz CBRS-FSS band, such that potential sources ofinterference may be more optimally detected and managed. That is, thebeacon detection range should be sufficient to not only detect anysource of potential interference, but also to enable the central serverto better plan the spectrum utilization across the region managed by thecentral server. The greater the range of a beacon, the more APs it willencounter. Each of these APs may then be directly managed by the centralserver to ensure a more efficient global optimization solution.

The utilization of radio beacons associated with C-band APs (as well asother spectral transmitters), as described above, enables theidentification of the beacon transmitter, as well as the detection andthe determination of the FSS interference contribution from eachindividual transmitter. However, successful detection of a beacontransmission is subject to finite range, or maximum path loss, which isa significant consideration. That is, the ability to detect the beaconsmust achieve a minimum sufficient level such that the central server isable to observe all significant interference, and thereby implement theclosed loop system to manage and control interference to allow sharingof the band with both satellite users and other terrestrial radiocommunications.

For example, in order to detect transmitters causing potentialco-channel interference, the central server must, under presentregulations, consider distances up to 150 km from the FSS site.Additionally, the beacon detection systems described above should alsobe capable of determining the effects of aggregation of alltransmitters, in the entire 500 MHz (e.g., C-band), and up to 40 km fromthe FSS site. Until new operating regulations are adopted, theseconservative limits must be addressed by the present systems andmethods. Nevertheless, it is important to note that the conservativelimits of the present regulations were defined according to theconventional techniques, which did not include the closed loop system ofthe present embodiments. As described above, the present techniquesenable significantly lower transmission power and distance limits fromthe FSS site, but without reducing the interference protection to thesite.

More particularly, for the lowest elevation angle of 5 degrees, and anAzimuth of 0 degrees, the satellite dish would be assumed to have a gainof 14.5 dB. For a 1 W transmitter in a 10 MHz bandwidth, the requiredminimum path loss is then 180.5 dB for a single co-channel interferencesource. For high elevation angles, the minimum link budget would then belower than the minimum path loss value, thus yielding greater beacondetector ranges. For this example, implementation of WSJT in the beaconinfrastructure described above will then advantageously allow a maximumpath loss of 198 dB at a transmitter power of 1 W with an isotopicantenna. In the case where directional antennas are implemented insteadof (or in addition to) an isotropic antenna, the link budget may be evenfurther extended, as described in greater detail below.

Accordingly, for a one-minute Private Use Area (PUA) 43 transmission,e.g., containing 28 characters sent at 0.5 characters per second, thetransmission can still be copied down to approximately 27 dB below thelevel of receiver noise. Post-detection averaging can yield nearlyanother 6 dB improvement in 0.5 hours of alternating one-minuteintervals of WSJT transmission/reception. PUA43 is cited in this examplebecause of its decoding capability at low SNR values. Fast detectionusing PUA43, however, requires very accurate alignment of the receiverlocal oscillator with the transmitter. Because the LNB frequency offsetmay span several kHz, costly GPS discipline and/or Rubidium basedfrequency reference techniques are often further required. Furthermore,an additional margin of 33 dB for WSJT can be quickly consumed by anincrease in the number of transmitters. It should be noted though, thatthe gain of a satellite dish is typically defined over a relativelysmall angle, and within these small angles that this co-channelconsiderations are significant.

According to the innovative systems and methods herein, the beaconinfrastructure advantageously implements a beacon format that (i)carries necessary information, such as the unique Radio Access ID usedfor identification, (ii) supports significantly lower SNR values, (iii)is measurable at the receiver, (iv) is able to utilize existing receiversystems, or alternatively implement lower-cost transmitters andreceivers, and (v) supports a multiple access scheme that enablesimplementation of a large and/or scalable number of transmitter beacons.WSJT techniques are described herein by way of example, and should notbe interpreted in a limiting sense. The present embodiments may alsoimplement other modulations schemes, such as WS propagation reporting,or schemes used in IoT applications, such as Lora or Ingenu. In Ingenu,for example, random phase multiple access scheme has a maximum path lossof 176 dB for 1 Mbit/s signal. In an exemplary embodiment, theinformation requirement for the beacon does not require such as highspeed, 1 Mbit/s, therefore the link budget can be accordingly increasedwith a much lower speed. As described above, some LTE modulation schemesadditionally utilize Zadoff-Chu (ZC) functions/sequences.

The present embodiments are thus able to calculate loss for a UEutilizing LTE as equal to −53.9 dB+75 Log(D) (e.g., D in meters), in ameasured 3.5 GHz propagation model. In this example, the beacon range iscalculated according to a worst case operational scenario, where loss isassumed to be greatest with increasing distance below clutter in aresidential morphology. According to these assumptions, the upper limitof the detection range is calculated to be 2.7 km. In practicalapplications though, different from this example, other morphologies ina typical city environment may yield detection ranges of up to 36 km,whereas rural morphologies may yield even greater detection ranges. Inthe case where the infrastructure described herein is implementedprimarily (or entirely) for small cell use below clutter, the effect oftransmitters beyond a 200-220 dB maximum path loss is likely to beinsignificant with respect to the parameters described herein, andtherefore these conventional maximum path loss requirements aresignificantly more conservative than would be required according to thepresent dynamic closed loop system. See also Table 3, below.

In another example, assuming the minimum path loss to be approximately180.5 dB for co-channel interference, for a 14.5 dB satellite gainhaving a minimum elevation angle of 5 degrees, 0 degrees Azimuth, and asingle 1 W transmitter in a 10 MHz bandwidth for a single interferer,then a 180.5 dB yield is obtained at a minimum distance of 1300 m.Beyond this distance, a single interferer would increasingly contributeless than the present FCC interference limit, that is, as the distancefurther increases. Further to this example, by doubling the distance to2600 m, the loss would be 203 dB, and the same interference source wouldthen be contribution less than 1% of the FCC threshold limit. In thisexample, the main beam of a satellite having a Full Beam-width HalfPower point of 5 degrees is considered. Implementation of the presentbeacon detection systems and methods on existing conventional satellitesystems link budgets of approximately 200-220 dB would thus enablemeasurement and control of all significant interferers within the mainbeam of the satellite. This particular example represents a worst casescenario, in the sense that an FSS with higher elevation angles wouldrequire a lower protection budget, and thus support a greater beacontransmission detection range.

At present, the United States contains a relatively large number ofregistered FSS sites across the country (e.g., approximately 4700), thepositions of which correlate fairly closely with the population density,and thus the relative levels of mobile use by such populations.Theoretically, a number of the registered FSS sites may not be in use,it is nevertheless believed that the number of sites that are actuallyin use is quite high, and may even exceed the number of officiallyregistered FSS sites when unregistered FSS sites are considered.However, unregistered FSS sites that consider future mobile use for thisspectrum are more likely to seek registration. Accordingly, in the casewhere different APs are likely to share the 3.7-4.2 GHz spectrum, theseAPs are likely to affect more than one FSS site within range of the AP(e.g., registered and unregistered).

The detection range of an FSS site might be seen as limited, whenconsidering only that FSS site and its beacon detector individually, andalso compared with present limits of 150 km and 40 km. However, if allof the beacon detectors of the infrastructure are considered together,the detection range may be significantly increased. Specifically, byimplementing a beacon detector at each FSS site, and then networking allof the beacon detectors to the central server/SAS, the detection rangeis effectively extended considerably beyond the 2.7 km that might beexpected according to the propagation model calculations describedabove. Other morphologies may support significantly higher distances dueto lower attenuation losses. According to the present embodiments, thedetection range can be extended even further through the calibrationtechniques of the propagation model using the real-time measurements ofthe MBP, as also described above.

For example, when a beacon is transmitted (e.g., by a new AP requestingto transmit) below the capability of the individual site to detect thebeacon, the broadcast beacon still may be detected by other beacondetectors (i.e., at other sites) during the initial registration processof the AP/transmitter, and without causing significant co-channelinterference. The present systems and methods thus advantageouslyutilize beacon detections from other sites (whether registered orunregistered) to effectively extend the range of beacon detection forthe first FSS site of interest. The APs from other sites would not causeany significant interference to the local individual FSS. Nevertheless,through use of the larger network of beacon detectors and the MBPsystem, it is possible to accurately determine the other APs'contribution to blocking and total aggregation effect, with respect tothe co-channel, first, and second interference limits at the individualFSS. Where the other APs are within the control of the central server,the central server is further enabled to more effectively manage theoutside APs. Additionally, the present embodiments further enable thecentral server to effectively detect beacon transmissions according tothe radio access point information used in the propagation measurementsdescribed above.

Thus, as each beacon detector reports to the central server(s)/SAS, thebeacon transmissions across the entire country (or area of beaconinfrastructure deployment) are detectable anywhere where people live, asemphasized below with respect to FIG. 15. That is, a beacon transmittedon the east coast of the country is detectable with respect to an FSSsite on the west coast, through the central server and the reportingsystem of the infrastructure embodiments described above.

FIG. 15 is a graphical illustration depicting a plot 1500 of anaddressable population 1502 (in percent) with respect to a radius 1504(in km) of an exclusion zone (e.g., first area zone 1104, FIG. 11A).Plot 1500 is therefore of particular value for use in estimating overlapof coverage according to the embodiments described above. Coverageoverlap is an important consideration in LTE systems. In an exemplaryembodiment, plot 1500 illustrates a statistical analysis of the U.S.population based on U.S. census data sets (ESRI) showing the averageeffects of an exclusion zone radius around each of the 4700 FSS sitesdescribed herein. This analysis enables effective removal from radiocoverage of portions of the population around the respective FSS sites.For example, with an exclusion zone radius of zero around each FSS site,approximately 99% of the U.S. population would be within the coveragearea. In comparison, with an exclusion zone radius of 25 km,approximately 10% of the U.S. population would be within the coveragearea. Accordingly, the positions of these FSS sites collectively provideradio coverage for nearly the entire U.S. population (e.g., alsoconsidering the unregistered FSS sites to reach the greater-than-4700number).

In the example depicted in FIG. 15, a simplest path loss model is ableto assume that the received power (in dBm) may be calculated accordingto:

Ω_(dB)(d)=Ω_(dB)(d ₀)−10B _(eta)Log₁₀(d/d ₀)+e _(r)   (Eq. 1)

where d represents the distance in meters, and Ω_(dB)(d₀) represents thereceived signal power at a known reference distance in the far field ofthe respective transmitting antenna, which may be 1 km for a macrocell,for example, 100 m for typical outdoor microcells, and/or 1 m for atypical Pico-cell. In contrast, the value for Ω_(dB)(d₀) will bedependent on the frequency, antenna heights, gains, etc., as well asother environmental factors. B_(eta) represents the path loss exponentparameter, and will be more dependent on the cell size and the localterrain. In some embodiments, the path loss exponent B_(eta) may rangefrom 3 to 4 for a typical urban macrocell environment, and from 2 to 8for a microcellular environment. In the exemplary embodiment, the lossexponent B_(eta) is determined by system 1200 (e.g., central server1202) for each individual interferer, and each such exponent value maybe used to further build the detailed local propagation model. The terme_(r) represents a zero-mean Gaussian random variable (in dB), andrepresents the error between the actual and estimated loss.

Shadow and corner effects will cause variance in the measured receivedsignal power Ω_(dB)(d) (e.g., by beacon detector 1214, FIG. 12).Accordingly, the statistical variation of the measured Ω_(dB)(d), causedby shadowing, may be modeled as being log-normal distributed accordingto the following equation:

pΩ _(dB)(x)=(1/_(√2π δΩ))exp{−(x−U _(Ω))/2 δ_(Ω) ²}  (Eq. 2)

where δ_(Ω) represents the shadow standard deviation. Thus, a moreaccurate path loss determination will result in in smaller values beingobtained for δ_(Ω.) In the case of macrocells, values for δ_(Ω) mayrange between 5 and 12 dB, with 8 dB representing a more expected value.In this example, δ_(Ω) may be observed to be substantially independentof the path loss distance d.

As described further herein, the present beacon infrastructure andbeacon transmissions are of particular use in the dynamic and real timedetermination of the path loss model. For example, when a beacon istransmitted by a radio AP and detected by the beacon detector (e.g., atan FSS site) the transmitted beacon will provide a path loss valueaccording to Eq. 1, above. From this detected value, the central servermay determine the path distance d according to several conventionaltechniques, including use of the known geographical coordinates for bothof the AP and the FSS site, which may, for example, be pre-loaded intothe central server database. In some instances, and particularly at theinitialization phase, an AP may not have any UEs associated there with,and thus no additional interference from the UEs will be calculated.Nevertheless, some statistical variation in the measured received powerwill still occur, due to multipath and shadowing effects, but may beaccounted for by the value for e_(r).

In an exemplary embodiment, a determination scheme for a propagationmodel calculates the additional interference for both the APs and theUEs. After the initial determination, subsequent measurements of beaconpath loss will advantageously provide further information useful forcalculating the value of e_(r). In this example, e_(r) may berepresented by a probability density function, which is a zero-meanGaussian random variable. An average value for this probability densityfunction may then be determined from repeated measurements, and willprovide an accurate estimate for P_(L)(d₀)−10B_(eta)Log₁₀(d/d₀). In someembodiments, the same measurements are further useful to determine thevalue for B_(eta) according to curve fitting mechanisms and othermathematical techniques.

In most instances, the path loss exponent B_(eta) will be stronglydependent on the cell size and the local terrain. Accordingly, thepresent techniques are further advantageous in that they may be extendedto other locations in a FSS locality (i.e., the FSS cell site) todetermine a representative value of B_(eta) for that locality.

The techniques herein are still further effective for modeling theeffect of UEs on the dynamic system model. For example, once theparameters of Eq. 1 have been established, and the AP is authorized totransmit (according to one or more of the processes described above) thecentral server may be further configured to assign an EIRP power suchthat the authorized AP transmissions will be below an interferencethreshold, such as a predetermined threshold. In the exemplaryembodiment, central server may determine the initial association of UEswithout first performing such calculations. In this case, after theinitial association, subsequent calculations may be performed torepresent the interference effect from the UEs, and the transmitter EIRPmay be dynamically modified to represent the AP EIRP, as well as the sumof UE transmitter powers associated with that AP. According to thisembodiment, a more accurate interference calculation may be performed bythe central server for extending the spectrum access sharing system.

In this example, the central server is configured such that theeffective transmitter EIRP of the AP reflects, in real-time, the numberand type of UEs associated with that AP. The type of UE may besignificant, in that the type may determine the duty cycle of thetransmission (e.g., LTE FDD vs. LTE TTD). The number and type ofassociated UEs may be communicated, for example, over a fixed lineconnection (e.g., AP data link 414, FIG. 4) from the AP to the centralserver or SAS. By using a fixed line connection in such manner, thesystem avoids having to transmit this information with the beacon eachtime there is a change to the number of associated UEs. In someembodiments, the signaling load may also be reduced by providing to thecentral server a predetermined assumption for the number of UEsassociated with the AP, and this presumed value may be used as athreshold for the relevant calculations for the effect of UEs oninterference. In other embodiments, the value is based on historicrecords (e.g., day use vs evening use). This threshold presumptionfurther provides a level of safety margin for the calculations when thenumber of associated UEs is actually fewer than the presumed value. Inthis case, when a presumed threshold UE value is used, the centralserver need only be updated when the actual number of UEs exceeds thisthreshold value, whether communicated over the fixed connection ortransmitted with the beacon. According to this exemplary configuration,the interference effect of UE power is a function of the multiple accessscheme of the particular UE. For example, in the case of LTE TDD, theduty cycle of the transmission will modify the effective interferenceeffect. In the case of CBRS device, a maximum value EIRP may be 23 dBm.

In these examples, the effective transmitter EIRP essentially resemblesa single point source with respect to the interference calculations.That is, a single received power value may be used to represent the APand its associated UE community. According to the present embodiments,this particular technique is effective due to the relatively smallcellular area of the AP (i.e., radius of coverage) in comparison withthe distance to the FSS site, which may, in this example havesubstantially similar dimensions. Accordingly, higher-power APs may bedeployed according to the present techniques that distance is fartherfrom the FSS site.

An alternative, or additional, safety margin for locality may beprovided using the error term e_(r) featured in Eq. 1, above. In anembodiment, the error e_(r) influences the link budget by providing asafety margin for the initial beacon transmission, which prevents theparticular beacon signal from being used to interfere with the FSS sitesin the local area. In one example, the link budget is optimized to allowa highest reasonable value for the error term e_(r), which will therebyproduce the highest potential link budget. This exemplary configurationfurther enables the central server (or other detectors) to identify eachseparate AP from the beacon detection system of the FSS site, anddetermine the interference effects of each particular AP.

In some embodiments, these techniques are further applied to theeffective EIRP of an AP such that the determined value for the EIRP issufficient to include the UEs associated with that AP. Accordingly, astatistical distribution associated with the particular AP will modelthe effect of multi-path and shadowing for both the AP and itsassociated UEs. Because the AP cellular area, and thus its radius ofcoverage, is considered relatively small in comparison with the distanceto the FSS site, the interference may be approximated to a point source.The individual power of the associated UEs will be, in this instance,significantly smaller than the power of the AP, and therefore anyadditional increase to the parameter δ_(Ω) (e.g., from a building cornereffect (FIG. 12B)) may be considered relatively insignificant.Accordingly, in some examples, a lower bound of propagation path loss,such as from conventional modeling techniques, may be used for thedetermination of initial beacon transmission power. This lower boundrepresents the most conservative static and value that will ensure nosignificant interference.

The value of error e_(r) further extends to determinations of ongoingAP/associated UE use. For example, when a particular AP is authorized totransmit at a particular power on a particular channel, there will be anexpected statistical variation to the measurable interference that theFSS site will experience. Using this expected statistical variation, thecentral server may be configured to use a higher value for the errore_(r) than would be required for the conservative conventionalpropagation model. In one example, the central server is configured touse the statistical averaging of path loss value for AP transmitterpowers across the locality, such that somewhat higher transmitter powersmay be authorized, but without increasing the risk of interference tolocality. By allowing higher transmitter powers within the locality,significant increases to the coverage and capacity of the system areadvantageously realized.

In the examples described above, a 4 dB improvement to the transmitterpower (and thus the link budget as well) is realized in comparison withconventional techniques that are limited to using only the lower boundof propagation loss (e.g., based on known for macrocell parameters).This 4 dB improvement though, only reflects the initial gains from theimproved calculation model. The present systems and methods achievestill further improvements to the link budget due to the real-time MBPconfiguration of the network, which may dynamically optimize the modelsuch that improvements of up to 8 dB or greater are realized duringoperation.

The improved MBP propagation model of the present embodiments thereforeprovides a number of significant advantages in comparison with theconventional modeling techniques. The present techniques are able toensure that an initial beacon transmission will not cause interferenceto the FSS site. Indeed, according to the present techniques, thecentral server may be configured to utilize the highest value of beacontransmission power to actually enhance the link budget. These techniquesfurther enable the more efficient use of the allocation of transmitterpowers based on derived information of APs within a locality, which willrealistically yield a 4-8 dB improvement in transmitter power. Thedynamic propagation model of the present embodiments is also scalable,and may be extended to model the AP itself, and/or its associated UEs,using the effective EIRP of the AP.

The number of associated UEs for a given AP may thus be presumedaccording to a predetermined threshold, and/or updated in real-time overa fixed communication link of the network to reduce signaling load.Moreover, the present systems and methods are capable of dynamically“learning” the average number of UEs associated with an individual AP,and such learned values may be retained (e.g., by the central serverdatabase), thereby further reducing the potential signal load. Theselearned values may, for example, further includes a statisticalassociation of UEs according to a time of day, week, etc., and applythese learned values to the calculations/models as well.

In the example depicted with respect to FIG. 15, ZC sequences are knownto be utilized in LTE systems such as the 3GPP LTE air interface in thePrimary Synchronization Signal (PSS), the random access preamble(PRACH), the uplink control channel (PUCCH), the uplink traffic channel(PUSCH), and the sounding reference signals (SRS). In such systems,orthogonal ZC sequences are assigned to each LTE eNodeB, and thetransmissions of these sequences are multiplied by their respectivecodes. Accordingly, the eNodeB transmissions are uniquely identified,while the cross-correlation of simultaneous eNodeB transmissions and theinter-cell interference are reduced. In an exemplary embodiment, thepresent systems and methods implement ZC sequences to achieve furtheradvantages according to the valuable properties thereof.

A ZC sequence is a complex-valued mathematical sequence which, whenapplied to radio signals, gives rise to an electromagnetic signal ofconstant amplitude. Cyclically shifted versions of the ZC sequence, whenimposed on the signal, result in zero correlation with one another atthe receiver of the signal. A generated ZC sequence that has not beenshifted is referred to as a “root sequence,” and such sequences exhibitthe useful property that cyclically shifted versions of themselves areorthogonal to one another, provided that each cyclic shift, when viewedwithin the time domain of the signal, is greater than the combinedpropagation delay and multi-path delay-spread of that signal between thetransmitter and receiver.

It has recently been proposed that a 100 MHz portion of the 500 MHz ofC-band spectrum be allocated for mobile use (e.g., LTE). This proposedallocation would leave the remaining 400 MHz available forimplementation of the MBP scheme for spectrum sharing. As describedabove, some embodiments utilize a guard band for transmission of thebeacon signal. Under these new proposals, the ZC sequence beacons may bealternatively or additionally utilized for the same purposes within thisnew mobile band, and without causing interference to other mobile usersof that band. Under this new proposal, users sharing the 400 MHzspectrum portion could be provided additional access to this new 100 MHzportion of mobile spectrum for beacon transmissions. Users that do notaccess this 100 MHz portion would still be able implement the adjacentguard band solution described above. Alternative proposals allocate 200MHz of the available spectrum, and/or upper or lower portions thereof.The person of ordinary skill in the art will understand that theprinciples of the present embodiments are not limited to 100 MHz or 200MHz, or upper or lower edges of a given spectrum, such as the C-band.

While the propagation characteristics of a different band (e.g., new100-300 MHz allocation portion) for beacon transmission may be differentthan that of an adjacent guard band in close proximity to the channel inuse, assuming implementation in the 3.7-3.8 GHz spectrum, MBPmeasurements in this new band are expected to indicate a moreconservative protection scheme, since the measurements thereof wouldyield lower propagation losses than experienced at higher frequencies.Alternatively, the central server may further utilize a calibrationparameter to correct for this propagation loss difference. The systemsand methods herein are also advantageously capable of further adaptationsuch that the beacons utilize other radio bands, such as the CBRS band,as an alternative solution where warranted.

Implementation of this new proposed 100 MHz portion (or similar) willinfluence the choice between an adjacent guard band and this differentband according to such considerations as (i) beacon range (e.g., due todifferences in beacon transmitter power), (ii) similar propagationcharacteristics, and (iii) the ability to accurately predict the actualchannel characteristics of the signal channel as well as access rightsto this new mobile band for transmission of the beacon. It is expectedthat this new 100 MHz band portion, if implemented as proposed, will beused for 5G Mobile, in which case the existing infrastructure for LTE ZCfunctionality may be advantageously utilized to transmit the beaconfunctionality described herein.

As described above, WSJT techniques achieve notably superior SNR valuesbelow the receiver threshold. However, these techniques require veryaccurate alignment of the receiver local oscillator with the transmitterfor successful and fast detection. As also described above, the phasedrift (phase noise) of the LNB down conversation may span several kHz,and therefore typically require expensive GPS discipline Rubidiumsources. Conventional ZC implementation techniques may require, forexample, a 1 W/3.25 MHz transmitter power, a high gain multiple-inputand multiple-output (MIMO) antenna (e.g., steerable such that, as gainincreases, so does the antenna directivity, thereby reducing the angularfield of view) as a separate beacon detector or satellite gain, as wellas a low-noise receiver, to achieve 6 dB higher than WSJT performance,as illustrated in Table 3, below, due to the receiver antenna gain. Asdescribed above, 198 dB may be realized in the case of an isotopicreceiver. Alternatively, the implementation of WSJT with MIMO orsatellite gain would likely yield higher than ZC values. According tothe present techniques, however, such obstacles are overcome, andparticularly with respect to the LNB down conversation.

In an exemplary embodiment, the present techniques convert (e.g., at thecentral server) a linear convolution to a circular convolution byrepeating one ZC sequence shoulder-by-shoulder. Through this innovativetechnique, applied to the beacon infrastructure described above, theindividual computation speed is reduced from N*N, to N*log N, which willthereby avoid an N-squared computation problem seen using conventionalmodeling techniques.

This exemplary technique therefore utilizes ZC sequences to resolve thebudget for the beacon-based systems and methods described above.According to an exemplary calculation, the maximum path loss (MPL) maybe represented by the equation:

MPL=Tx−Rx+Gain(Rx)+SNR   (Eq. 1)

Where Tx represents the transmitter power of the beacon (i.e., ERIP) perMHz, Rx represents the sensitivity (noise power per MHz=NoiseFigure*k*T*B) of the receiver, where T=300K and k=1.38 10 exp(−23),Gain(Rx) represents the gain of the beacon detector, and SNR representsthe signal-to-noise ratio value below the receiver sensitivity (e.g.,coding gains, etc.). Accordingly, the budget may be thus calculated inconsideration of the values depicted in Table 3, below.

TABLE 3 ZC Budget (3.25 Mbits baud rate) value units Transmitter Power:25 dBm/MHz 1 W per 3.25 MHz Bandwidth 3.25 MHz Rx Noise Power −112dBm/MHz (Noise FIGURE = 1.5 dB) Rx S/N −30 dB Rx Antenna/Satellite Gain37 dB Max Path Loss 204 dB

It can be noted, from Table 3, the significant role played by thereceiver gain. In at least one embodiment, by directly using the actualsatellite dish gain with in-band detection having a post-LNB ofapproximately 37 dB (e.g., for a 2 m dish), a 204 dB link budget can beachieved. In an exemplary embodiment, the transmitter power Tx of thebeacon is further increased using the guard band. In some embodiments,the SNR and/or the receiver gain are also further increased. Theseadditional increases may be of particular advantageous value in the casewhere both external and in-band satellite beacon detection are performedtogether.

Table 4, below, illustrates the change in beacon range, below clutter,for use in (i) residential, (ii) residential/commercial mixed, and (iii)high density commercial implementations. In the exemplary MPL budgetsdepicted in Table 4, ZC sequences are implemented at 3.25 MHz, withreceiver power established at NF=1.5 dB, and T=300K. In this example,the beacon Tx 25 dBm/MHz (i.e., at 3.25 MHz), and the AP transmitterpower is 20 dBm/MHz (at 10 MHz) for a class A CBRD.

TABLE 4 Beacon Range Beacon Range Beacon Range (high density MaximumPath (residential, (residential/commercial commercial Transmitter Lossfor ZC: below clutter) or mix below clutter) below clutter) Power Single[D > 200: [D > 200: [D > 200: (dBm) Interferer −53.9 + 75 LogD] −31.2 +40 LogD] −31.2 + 40 LogD] 25 192 dB 1.9 km 10.5 km  6.8 km 35 202 dB 2.6km 18.6 km 12.1 km 42 209 dB 3.2 km 27.9 km 18.1 km

These innovative techniques for extending the ability to detect thebeacons well beyond the beacon transmission range provides furtheradvantages to satellite protection schemes. For example, conventionalsatellite protection regulations require consideration of distances ofup to 40 km for blocking, and up to 150 km for the co-channelimplementations described above, both of which are significantly greaterthan the transmission range of the beacons. Nevertheless, considering alink budget greater than approximately 210.5 dB (i.e., 30 dB above 180.5dB), for the worst case scenario of the lowest satellite elevation of 5degrees, at an azimuth of 0 degrees, the integral power for small celldeployments, below clutter and beyond the beacon range boundary, willgenerally be insignificant, as illustrated below with respect to Table5. In the case where the small cell integral power is considered to begreater than this insignificant amount, the integral power may beaddressed, if necessary, by slight increases to the protection limit.

TABLE 5 Residential/ High density Residential commercial mix commercialFree space below clutter below clutter below clutter a 44.3737141 −53.931.2 38.7 b 20 75 40 40 Small cell 37 20 20 20 power/dBm Cell size/1000000 1000 500 100 m{circumflex over ( )}2 Link budget 150000 12001200 1200 boundary/m Integral −111.152828 −156.3941159 −127.3545513−127.8648512 power outside boundary/ dBm

FIGS. 16A-16B illustrate data tables 1600, 1602 for satellite protectionMPL with respect to a single AP, and 800 APs, respectively, within thesatellite beam width. In the exemplary embodiments illustrated in datatables 1600 and 1602, the MPL is 192 dB, which is capable of managing800 CBSDs, which is indicated by the values contained within data table1402 specifically, representing a worst-case scenario. Small cellconsiderations are described above. Macrocell interferenceconsiderations may be calculated with respect to Table 6, below.

TABLE 6 Below Clutter Above Clutter Above Clutter ResidentialResidential Residential/ (km) (km) Commercial Elevation Gain [−53.9 +[−100 + Mix (km) (degrees) (dB) 75 logD] 75 logD] [−13.3 + 50 logD] 514.53 2.47 10.18 18.95 10 7.00 1.96 8.08 13.40 15 2.60 1.71 7.06 10.9420 −0.53 1.56 6.41 9.48 25 −2.95 1.45 5.95 8.48 30 −4.93 1.36 5.60 7.7435 −6.60 1.29 5.32 7.16 40 −8.05 1.24 5.09 6.70 48 −10.03 1.16 4.79 6.12

It is noted that, with respect to the values illustrated in Table 6, thecalculations do not assume the use of MIMO antennas or real gain of thesatellite dish (37 dB in the case of a 2 m dish). The satellite gain iscalculated using the standard ITU equation for interferencecalculations. In such cases of MIMO implementation, the interferenceconsiderations are presumed to be worse. For the macrocell calculationsillustrated in Table 6, the exemplary transmitter power (EIRP) is 37dBm/MHz (50 W in a 10 MHz band), and the interference is assumed to beequal to 1% (−20 dB) of the satellite threshold of −129 dBm/MHz. Thisassumption therefore effectively takes into account more than one singleinterferer with a safety margin. The calculations illustrated in Table 6further take into account the satellite elevation, satellite dishazimuth of 0 degrees and thus the gain, for this form of co-channelinterference. These calculations additionally implement the exemplarymeasurement model described above, which is suitable forresidential/commercial use. A rural-based model, on the other hand,would predict larger propagation distances, and the macrocells may beconstructed to be above clutter for greater coverage. Nevertheless, thefirst column of Table 6 illustrates a residential case below clutter.

According to the exemplary calculations included in Table 6, that can beseen that a safe macrocell distance, according to these parameters, isfound between 10 km and 19 km for low elevations (e.g., 5 degrees), butmay be as low as between 5 km and 7 km at 35 degrees. Given the densityof FSS sites in residential and residential/commercial type areas acrossthe country, where the “blocking effect” is greatest, the use of 3.7 GHzfor macro-cells may not be practical. That is, when the particulartransmitter is that far from a single FSS site of concern, it is highlylikely that the transmitter is closer in distance to a different FSSsite. In this example, a relatively low transmitter power (in comparisonwith normal power) is assumed for the macro-cell. In this case, rangeextensions using MIMO antennas may be less practical, and insteadcontribute to interference and possibly increase the safe operatingdistances.

As illustrated in Table 6, the calculated results in the case of belowclutter indicate that the safety distance is approximately 1.3 km for anin-band transmitter at 35 degrees. It should be noted, that in thisexample, a higher transmitter power (Cat B Rural) is used for thecalculation than would be the case for a typical indoor CBRS AP. Thepresent techniques are not bound by such limitations though, because the3.7 GHz spectrum is not generally considered to be particularly suitablefor macro cellular coverage due to its poor propagation, andparticularly with respect to handset devices that are limited intransmitter power for the return path, and therefore cannot utilize MIMOof significant proportions. Nevertheless, the present embodimentsconsider the 3.7 GHz spectrum because it may still affect the FSSsite(s) of concern. Additionally, there exist other low frequency bandsthat would not cause interference to the FSS site, and which may bere-purposed for similar use.

Accordingly, these macrocell considerations further emphasize how the3.7 GHz spectrum is of particular value for use with small cells, asdescribed above, similar to the power bands utilized for CBRS, namely,the 1 W, 4 W and 50 W power bands. The present embodiments still furtherdemonstrate the advantages obtained through utilizing beacons in themacrocell, wherever such implementation is possible, and particularly ininstances outside of the United States regulatory structure.

In another embodiment, number range reuse techniques provide analternative process to increase the maximum path loss for beacondetection. In this example, the transmitted beacon includes informationfor successful operation, including without limitation one or more of:(i) the unique ID of the AP; (ii) the transmitter power; (iii) thesignal channel(s) desired on which to transmit; (iv) the AP location;etc. In some embodiments, the present systems and methods limit theinformation included in the beacon so as to minimize the bit rate and/orduration of the beacon transmission that might potentially detract fromthe MPL budget or overall ability of the system to detect and rapidlyprotect from interference. In at least one embodiment, only the uniqueID of the radio AP is transmitted over the air, and other information istransmitted to the central server/SAS over a fixed network along withthe AP unique ID.

In this embodiment, supporting a number range of up to 1 billion (e.g.,for potentially all possible future IDs) would require a binary worklength of 30 bits. Reducing this binary work length to 16 bits wouldonly allow a number range of approximately 65 thousand, which would notbe sufficient for this foreseeable future use. Such reduction though,would nevertheless increase the MPL budget by as much as 3 dB, whilealso reducing the speed of identification by nearly a factor of two. Thepresent number reuse techniques realize the advantages obtained byreducing the binary work length, but without the correspondingconventional disadvantages of the reduced number range. These advantagesare achieved by allocation to each FSS site a cell around the site inwhich each AP has a unique ID, but these unique IDs may besimultaneously used outside of the cell.

FIG. 17 illustrates a patterned grid region 1700 including a pluralityof contiguous grid blocks 1702. In the exemplary embodiment, contiguousgrid blocks 1702 are illustrated as being substantially hexagonal forease of explanation. In this example, a hexagonal shape approximates around coverage area having a somewhat uniform radius from center, andwhich does not include gaps between respective coverage areasrepresented by grid blocks 1702. Additionally, the hexagonal boundaryshape simplifies the discussion to ignore overlap of adjacent gridblocks 1702 (see e.g., FIG. 13, above).

According to the exemplary embodiment, the present systems and methodsmay utilize an 18-bit word, which would thus allow the reuse of 4patterns, and thereby accommodate approximately 65 k APs per cell. Inother embodiments, reuse of a greater number of patterns may be desired.Such higher reuse examples are somewhat similar in concept to FrequencyDivision Duplex (FDD) techniques used in cellular systems, where blocksof frequencies are used per cell with a reuse repeat pattern. In atleast one embodiment, APs having the same ID may be differentiated fromone another by use of triangulation by a network of beacon detectors.

According to the embodiment illustrated in FIG. 17, each of theindividual grid blocks 1702 in patterned grid region 1700 is assigned adifferent one of six individual use patterns (e.g., designated asletters A-G), and thus indicates a cellular reuse factor of 7. Eachindividual grid block 1702 therefore represents a different block of 65k numbers per lettered pattern, e.g., A65 k, B65 k, C65 k, D65 k, E65 k,F65 k, G65 k. Accordingly, similar to cellular network techniques, notwo blocks of 65K APs having the same pattern (i.e., one of A-G) areimmediately adjacent one another.

In an exemplary operation of patterned grid region 1700, a triangulationscheme according to the present embodiments enables spatial reuse of afirst grid block 1704 having pattern A. More particularly, thetriangulation scheme applied to grid region 1700 effectively separatesthe number range used in pattern A from being also used in immediatelyadjacent blocks 1706. As illustrated in FIG. 17, in each direction 1708from first grid block 1704, at least two grid blocks 1702 of differentpatterns (e.g., B-G) are interposed between first grid block 1704 andeach instance of a second grid block 1710 that uses the same pattern A.

In an embodiment, time division multiplexing techniques are implemented,in an alternative or supplemental manner, to further separate and extendthe reuse of number patterns A-G. For example, the system of patternedgrid region 1700 may be configured (e.g., at the central server) suchthat transmission in first grid block 1704 is controlled such that theAPs of first grid block 1704 transmit on even number days, while the APsof an instance of adjacent block 1706 transmits on odd numbered daysusing the same number range of the pattern (e.g., pattern A) of firstgrid block 1704. This time division technique is scalable, and thereforemay be further implemented to alternate transmission at the odd/evenminute level (or less) using the GPS technology and information withineach block 1702.

Referring back to FIG. 5, in another embodiment, beacon measurements maybe obtained utilizing the LNB (e.g., LNB 530), the dish, and/or the feedhorn of the earth station (e.g., earth station 504) of a particular FSSsite (e.g., FSS site 502). A beacon receiver (e.g., beacon detector 528)communicates over an operable data link (e.g., reporting links 540, 542,544, 546) to the central server (e.g., central server/SAS 510). In thisexample, the hardware of the particular dish/earth station may serve asan alternative to an outdoor beacon receiver and antenna, or multiplereceivers and antennas per dish, by tapping into each FSS antenna signaldistribution chain downstream of the LNB. The beacon may then bereceived at the down converted (IF) frequency of the in-band beaconsignal, and the central server may then avoid having to adjust the RSSIof the beacon with respect to the FSS dish antenna gain, due to thebeacon signal having been received using the FSS dish.

Alternatively, the present systems and methods may be instead (oradditionally) configured to utilize MIMO antennas to detect beacontransmissions. More particularly, instead of utilizing the beacondetection obtained after the LNB down conversion, an infrastructureaccording to this example may be configured to deploy an externalantenna covering the 3.7-4.2 GHz band, and which can be orientated inthe same direction of the satellite dish, or may be configured made suchthat it may sweep a 360 degree rotation with a narrow beam andcorresponding high gain. In this alternative embodiment, MIMO technologyachieves at least 37 dBi of gain over angular view greater than thesatellite beam width. A further advantage to this alternative techniqueis that a single external antenna may be deployed to cover the entireFSS site, which may contain many individual satellite dishes. In thisexample, only the single external antenna need be in operablecommunication with the central server. In at least one embodiment, aparabolic antenna is implemented, which realizes a 37 dBi gain, coveringthe 3.4-3.7 GHz band, with a beam width of 8.5 degrees that effectivelycomplements the beam width of satellites used in the C-band.

In some embodiments, the link budget is still further extended throughan innovative implementation of MIMO technology. For example, since theeffective interference contribution outside of the beam width of thesatellite is −10 dBi, which is approximately 47 dBi (37 dBi+10 dBi) lessthan that within the satellite beam, the most significant interferenceconsiderations are taken in the direction of the satellite dish, thatis, within the satellite beam. However, since the antenna may beconfigured (whether electrically or mechanically) to sweep a 360 degreefield of view, such use of an external antenna will require calibrationwith the satellites being protected, in order to accurately measure therelevant interference. In this embodiment, therefore, implementation ofthe external antenna provides at least a 10 dB improvement in maximumpath loss/range.

In one embodiment, the present beacon detection infrastructure furtherutilizes the measurement-based propagation models, described above, toextend the effective range of beacon detection. As described above, themeasurement-based propagation techniques enable the central server toregularly and/or constantly update the propagation model(s) of thenetwork, using information obtained from the multiple APs and beacondetectors that are integrated within the overall spectrum access sharingsystem. According to this MBP scheme, more accurate calculations of linkbudgets are obtained in the initial set up of channel allocations, andsubsequent beacon transmissions serve to verify successful operation.Through these MBP propagation techniques, central server isadvantageously configured to calculate not only the co-channelemissions, but also the first and second adjacent channel emissions toensure regulatory compliance of the network. This measurement scheme isalso further scalable to address the aggregate interference across the500 MHz band, for example, by calculating the relevant LNB blockingconsiderations. In one embodiment, such considerations may be limited at−60 dBm, or measured directly by the beacon detector as part of itsfunctionality.

FIG. 18 is a graphical illustration 1800 depicting comparative dataplots 1802 of dual-slope propagation models (i) at clutter, (ii) belowclutter, and (iii) above clutter, and for each morphology of (a) highdensity commercial, (b) residential, and (c) residential/commercialmixed classifications. In the example illustrated in FIG. 18, the pathloss (vertical axis, in dB) is plotted against distance (horizontalaxis, in meters) for each model, and all such models are charted againsta free space path loss plot 1804. In the exemplary embodiment, theresulting data plots 1802 represent empirical or tuned 3.5 GHzdual-slope propagation models, as well as the dual-slope log-distancepath loss models for all morphology/clutter classifications and freespace loss.

As shown in illustration 1800, the “below clutter” data plots 1802generally indicate the greatest path loss, whereas the “above clutter”data plots 1802 generally indicate the least amount of and path loss.Additionally, the high density commercial morphologies similarlyindicate greater amounts of path loss, whereas the residentialmorphologies indicate less path loss. Data plots 1802 are illustrated ingreater detail below with respect to Table 7, which further providesbreakpoint and slope values for each of the propagation models depictedas data plots 1802, and compares these values against relevant values ofthe single slope model.

TABLE 7 RESIDENTIAL/ HIGH DENSITY RESIDENTIAL COMMERCIAL MIX COMMERCIALBelow At Above Below At Above Below At Above Clutter Clutter ClutterClutter Clutter Clutter Clutter Clutter Clutter (m) (m) (m) (m) (m) (m)(m) (m) (m) Dual Break- D < 200 D < 250 D < 550 D < 300 D < 350 D < 250D < 100 D < 200 D < 400 Slope point Model 1st slope Break- D < 200 D <250 D < 550 D < 300 D < 350 D < 250 D < 100 D < 200 D < 400 point 2ndslope Single −10 + 21.3 + 30 + 35.2 + 20.5 + 9 + 39.2 + 9.2 + 42.4 +Slope 57logD 41.6logD 32logD 38.9logD 43.3logD 42.5logD 39.1logD47.7logD 29.5logD Model

Extensions of User Equipment Management

As described above, the beacon-based infrastructure and associatedtechniques are applicable to both UEs and APs, and that the potentialinterference effect of the UEs on the FSS site may be models usingeffective EIRP techniques. The examples described above are provided,without limitation, for APs at a “reasonable” distance from the FSSsite, and in the case where the radius of the AP coverage is relativelysmall in comparison with the distance of the AP from the FSS site (e.g.,approximately 500 m). The adoption of beacon transmitters withinindividual UEs though, may be impractical according to present-daycommunication network technologies, given the significantly large numberof UEs (and APs) presently in operation, and the reduced link budget ofthe UEs in comparison with that of the APs. Nevertheless, the rapidadvances in technology and communication network transmission may makepossible, or even necessitate, beacon transmissions from every UE in thenear future.

Beacon transmissions at the UE level, however, are of immediate value inthe case of APs relatively close to the FSS site (e.g., less than 500m), where the effects of the UE transmitter power may vary greatlyaccording to changing locations of the UE, such as when the UE is amobile device. Such variation makes the UE more difficult to model, butmuch of this difficulty is resolved by real-time beacon transmissionsfrom the UE. In one embodiment, the UE beacon transmissions may betriggered by a client on the UE device, which is instructed to operateaccording to management from the central server when the UE device comeswithin close proximity to the FSS site (and/or during an initialcalibration phase). In this example, only this small subset of UEs,close to the FSS site, are affected in this manner.

During an initial calibration phase, the UE beacons associated with aparticular AP may be measured at different locations around the AP, andsuch measurements, together with measurement of the associated APbeacon, are useful to determine the effective AP transmitter power, aswell as its statistical distribution, which will accurately estimate theinterference effect of the AP/UEs combination as a single point source,and as function of the number of UEs. The dynamic capabilities of thepresent system further enable the development of a more detailed AP/UEsmodel over time, during the real-time operation of the system. Thestatistical model that is derived therefrom is particularly useful todetermine the safe transmitter power of APs that are in close proximityto the FSS site, and to enable the central server to instruct one ormore UEs to reduce their individual transmitter power when needed, orfor the AP to reduce its power thereby reducing the coverage area andinfluence over the number of associated UEs.

Such instructions from the central server, namely, for the APs/UEs toreduce their allowable transmitter power, that further utilizecalculations that consider the shadowing or cornering effects ofbuildings (e.g., FIG. 12B) as mobile UEs move in and out of direct linesof sight from the FSS site. By reducing the allowed transmitter power ofthe AP itself, the central server is enabled to directly reduce the APinterference, as well as the geographic size of the AP coverage area.Reduction in the size of the AP coverage area will thereby also reducethe number of UEs that will be likely to be supported by the AP. In someinstances, such AP power reductions by the central server are a usefultool to reduce or eliminate the shadow effects of buildings on the celledges, where the relevant UEs may instead be supported by a CBRS ormacrocell. According to this advantageous configuration, the overalleffect on the system, from APs having associated UEs, is significantlymore deterministic.

The interference effect from the UEs themselves is considered withrespect to the exemplary values illustrated in Table 7, above, such thata dynamic propagation model may be derived therefrom. For this exemplarypropagation model, the respective transmitter powers associated with thedifferent devices is obtained using the values provided in Table 2, alsoabove. The relevant propagation model may be further constructed toimplement the following parameters included in Table 8, below.

TABLE 8 PARAMETER VALUE REFERENCE In-band interference −128.35 FCC§96.17(a)(2)&(b)(1) requirement (dBm/MHz) Reference antenna 32- FCC§25.209(a)(1)&(4) (dBi) 25 log10 (theta) CBRS BW (MHz) 20 NA Aggregatedblocking −60 FCC §96.17(a)(3)&(b)(2) requirement (dBm) Spectrum 1st adj40 ITU-R M.2109 7.2 mask channel (dB) 2nd adj 52http://www.jatit.org/volumes/ channel Vol65No3/21Vol65No3.pdf (dB) MaxTx UE 13 FCC §96.41 power (dBm/MHz) 37 FCC §96.41 Reference Passband 0.5FCC §96.17(a)(2)&(b)(1) filter insertion loss (dB) 1st adj 12.5 FCC§96.17(a)(3)&(b)(2) suppression (dB)* 2nd adj 33 FCC §96.17(a)(3)&(b)(2)suppression (dB)*

Using the parameters provided in Table 8, propagation losses between theUE and the FSS site may be calculated such that an interference level ofno greater than −129 dBm/MHz, for example, is achieved, as indicatedbelow with respect to the values provided in in Table 9. In the casewhere a pass band response is considered, the optimum interference levelmay be, for example, no greater than −128.35 dBm/MHz.

TABLE 9 Ele- va- Link budget (dB) tion Antenna 1st adj 2nd adj 1st adj2nd adj de- gain In-band blocking blocking emission emission grees (dBi)UE UE UE UE UE 5 14.53 155.38 89.33 67.73 115.38 103.38 10 7.00 147.8581.80 60.20 107.85 95.85 15 2.60 143.45 77.40 55.80 103.45 91.45 20−0.53 140.32 74.27 52.67 100.32 88.32 25 −2.95 137.90 71.85 50.25 97.9085.90 30 −4.93 135.92 69.87 48.27 95.92 83.92 35 −6.60 134.25 68.2046.60 94.25 82.25 40 −8.05 132.80 66.75 45.15 92.80 80.80 48 −10.03130.82 64.77 43.17 90.82 78.82

From the values obtained above, the central server may be furtherconfigured to calculate corresponding protection distances according tothe parameters depicted in Table 10, below (i.e., illustrating theresidential example, below clutter).

TABLE 10 Antenna Protection distance for UE below clutter (m) Elevationgain In-band 1st adj 2nd adj degrees (dBi) UE UE UE 5 14.53 617.08168.32 91.09 10 7.00 489.78 114.52 61.98 15 2.60 427.86 91.42 49.48 20−0.53 388.74 77.92 42.17 25 −2.95 360.87 68.84 37.75 30 −4.93 339.5962.20 33.66 35 −6.60 322.58 57.10 30.90 40 −8.05 308.54 53.02 28.69 48−10.03 290.35 47.91 25.93

According to the values depicted above, for the case of residentialbelow clutter, several determinations may be made: (i) at low elevation(e.g., 5 degrees), the UE exclusion zone is 617 m for co-channel use,however, the central server of the present system may utilize anoptimization algorithm with respect to the use of the 2nd Adjacentchannel, and then the 1st Adjacent channel, in zones around the FSSsite, effectively reducing the exclusion zone radius to approximately91-168 m, respectively; and (ii) at 35 degrees, the in-band UEprotection distance is approximately 322 m, and the 1st Adjacent bandprotection distance is approximately 57 m.

In this example, the exemplary values provided in Table 10 areapplicable within the range of the main beam, which has a half powerbeam width (HPBW) of approximately 5 degrees for a 2 m satellite dish.Outside of the main beam (assuming the “teardrop” shape of therespective zones described above), the gain rapidly approaches a valueof −10 dBi, thus accounting for the reduction of the in-band protectiondistance from approximately 617 m to 290 m, and the reduction in the 2ndAdjacent protection distance from approximately 91 m to 26 m. Further tothis example, it is assumed that UEs are likely to be inside buildings(which may typically require 17 dB of additional link budget). However,for ease of explanation, the above Table values are provided for a caseassuming that the UEs are located outside of buildings.

The analysis of the data provided in Table 10 may be similarly appliedto data for the at-clutter model, as provided below in Table 11, and todata for the residential above-clutter model, as provided further belowin Table 12.

TABLE 11 Antenna for UE distance at clutter (m) Elevation gain In-band1st adj degrees (dBi) UE UE 5 14.53 1554.23 246.17 10 7.00 1099.01154.11 15 2.60 897.33 117.18 20 −0.53 777.11 96.48 25 −2.95 695.07 82.9830 −4.93 634.51 73.36 35 −6.60 587.44 66.10 40 −8.05 549.50 60.40 48−10.03 501.63 53.40

TABLE 12 Antenna for UE distance at clutter (m) Elevation gain In-band1st adj 2nd adj degrees (dBi) UE UE UE 5 14.53 2541.03 744.18 514.85 107.00 2016.82 780.73 196.11 15 2.60 1761.85 470.31 118.14 20 −0.531600.75 328.26 82.45 25 −2.95 1486.00 248.36 62.38 30 −4.93 634.51197.74 49.57 35 −6.60 1328.34 163.09 40.97 40 −8.05 1270.52 138.01 34.6748 −10.03 1195.60 109.89 27.60

According to the values depicted above, determinations may also be madefor the case of residential above clutter: (i) at low elevation (e.g., 5degrees), the UE exclusion zone is 2541 m for co-channel use, however,the optimization algorithm applied to the 2nd Adjacent channel, and thento the 1st Adjacent channel, effectively reduces the exclusion zoneradius to approximately 515-744 m, respectively; and (ii) at 35 degrees,the in-band UE protection distance is approximately 1328 m, and the 1stAdjacent band protection distance is approximately 163 m and the 2ndAdjacent band protection at 41 m.

In this example, “clutter” is determined to be approximately 20 m, whichreasonably represents a three-story high building having UEs located onthe third floor. In practice, the UEs are likely to be inside thebuilding, and also located on other floors. Similar to the below cluttermodel considerations, above, outside of the main beam, the gain rapidlyapproaches −10 dBi rapidly, thus accounting for the reduction of thein-band protection distance to approximately 1195 m, and the 1stAdjacent band protection distance two approximately 110 m. Furthermore,at low elevations, a clear line of sight to the main beam is morenecessary, since there is less likely to be building interference abovethe building clutter. Accordingly, in practical applications, and FSSsite disposed above clutter would realistically experience lessinterference than the values provided in the Tables above. Theshadow/corner effects described herein are more likely to occur belowclutter (e.g., at or near ground level).

According to these models, it can be seen that UE migration may beanalyzed according to techniques similar to the other morphologiesdescribed herein. For example, with respect to the values for the 1stAdjacent channel, the above clutter protection distance of 744 m isreduced to approximately 168 m at a 5 degree elevation forbelow-clutter, and further to 57 m at a 35 degree elevation. Outside ofthe main beam, a similar protection distance reduction would berealized, i.e., from 109 m to 48 m. These modeling values thereforedemonstrate the proximity effect of UEs considered to be “close” to anFSS site, and therefore also the considerable value in implementing aUE-specific beacon to enable measurement of the actual UE interference,as well as the variance of the UE transmission caused byshadowing/cornering effects.

The embodiments herein this also demonstrate the particular value ofsumming an aggregate of UEs as a single reference point to model theeffective EIRP. In the exemplary embodiment, the UE beacon itself may betransmitted at −7 dB with respect to a Category A AP, −24 dB withrespect to a Category B rural AP, or −17 dB with respect to a Category Bnon-rural AP. The implementation of the present MBP techniques at the APlevel further advantageously enables the AP to determine when UE beaconsare activated, thereby further significantly reducing thesignal/computational load on the central server/SAS.

Beacon Receiver Implementations at Earth Station Sites

The beacon transmission/receiver infrastructure described above detectsbeacon transmissions throughout the system to determine, in real-time,the potential for interference at FSS earth station sites. The followingdescription provides further detail regarding the exemplaryimplementation, distribution, and operation of the exemplary beaconreceivers/at and among the FSS earth station sites. As described herein,the present systems and methods achieve significantly improvedmeasurements with respect to conventional techniques, and also moreaccurate estimates of interference levels in comparison with singledetector operations.

As described above, mobile communication systems may coexist withsatellite communication systems in the same CBRS band, but there arefewer than 20 such FSS sites across the United States, and havingrespective frequencies of operation restricted to the top end of theCBRS. Nevertheless, these FSS sites at present have large associatedprotection areas effectively segregating wireless and satellite users.System operators and the FCC are presently considering to additionalspectrum within the 3.7-4.2 GHz, 5.925-6.425 GHz, and 6.425-7.125 GHzbands for flexible use, such as for mobile communication (5G inparticular) in the United States. For ease of explanation, the UnitedStates is discussed herein by way of example, but is not intended to belimiting. The principles of the embodiments herein are applicable toother countries and their respective communication systems and networks.

With respect to the 3.7-4.2 GHz band, for example, 12 channels areprovided for the downlink satellite communications, with 40 MHz channelsspanning each polarization. At present, thousands of earth stationsoperate in this band across the United States, and require protectionfrom radio interference from other wireless services. In the UnitedStates, the FCC regulates the interference levels from such servicesthat share the same band.

In operation, the interference level from other wireless services may bemeasured (e.g., according to the techniques herein) or calculated (e.g.,according to conventional techniques or conservative propagation models)as described above, at a reference point disposed at the output of areference RF filter (RRF), such as between the feed horn and the LNB(described further below with respect to FIGS. 20 and 21). Inconventional systems, each implementation of proposed sharing isperformed in consultation with other FSS users, and using conservativeradio planning tools in models. Such implementations typically requiremonths to complete the necessary consultation and modeling of therespective proposal.

The innovative systems and methods described above though, provide newand improved techniques for coexistence of terrestrial wireless systems(e.g., including mobile communication systems) with satellite systems.The present techniques are drawn to a new operation model that expandsupon the promotion of CBRS at the 3.5 GHz range, as described above. Inthe exemplary embodiment, a coexistence mechanism is advantageouslyutilizes priority tiers, protection zones, and coordination through acentral server/SAS to plan use based initially on conservativepropagations models, but which is also dynamically adjustable inreal-time to the actual operational conditions of the system. In someembodiments, particular critical communication systems or subsystems(e.g., security or safety systems) may be assigned to have the highestpriority use of the larger system, or portions thereof.

As described in detail above, the beacon infrastructure of the presentsystems and methods is unique to this field of technology, andadvantageously provides a system for sharing the given satellite bandspectrum with other wireless users, while also protecting FSSinstallations. In the exemplary embodiment, low power level radiobeacons are implemented at each AP, and may be configured duringregistration to estimate in real-time the potential interference levelsto FSS sites, and in coordination by the central server. In theexemplary embodiment, each FSS site is provided with its own beacondetection system to measure the interference. The transmitted beaconsthat are detected at the FSS sites thus enable the real-timemeasurement-based propagation system for closed loop control ofinterference, and thus the capability to share the chosen spectrum band(e.g., the C-band). Specific embodiments of these beacon detectionsystems are described in greater detail as follows.

In an exemplary embodiment, the design and implementation of the beacondetection architecture at each earth station site is accomplished by oneor more of several types of individual detectors, and according to oneor more various implementation processes. In some embodiments, one ormore of the following detector types and implementation processes areutilized together for additional accuracy and reliability ofinterference measurements, calculations, and mitigation, and also forthe ease of integrating separate infrastructures as the present systemsand methods are scaled upward to accommodate more sites.

FIG. 19 is a schematic illustration of an FSS site 1900 configured toimplement protection scheme 400, FIG. 4. In the exemplary embodiment,FSS site 1900 includes one or more earth stations 1902, and one or moreof a platform-mounted beacon receiver 1904, a station-integrated beaconreceiver 1906, a co-located beacon receiver 1908, and an auxiliarybeacon receiver 1910. Earth stations 1902 are, for example, similar toearth stations 504, FIG. 5, and the several beacon receivers 1904, 1906,1908, 1910 (sometimes referred to as “BR” or “BRs”), may be eachconfigured to perform the functionality of beacon detector 528 at FSSsite 502.

In exemplary operation of FSS site 1900, each of beacon receivers 1904,1906, 1908, 1910 are further configured to receive beacon transmissionsfrom one or more beacon transmitters 1912, such as may be disposed at ornear an AP (not shown) or a UE (also not shown). In this example, beacontransmitters 1912 are similar in form and function to beacontransmitters 518, FIG. 5. In further operation, FSS site is configuredto communicate with a central server 1914. Central server 1914 is thussimilar to central server/SAS 510, FIG. 5, and may communicate with FSSsite 1900 according to any one or more of the communication linksdescribed with respect to central server/SAS 510.

In the exemplary embodiment, beacon receivers 1904, 1906, 1908, 1910 arelocated within, or in near proximity to, FSS site 1900 (i.e., a cableoperator plant). Alternatively, one or more of beacon receivers 1904,1906, 1908, 1910 are located outside of FSS site 1900, but function in asimilar manner (e.g., in communication with central server 1914 from aremote location). Additionally, the present embodiments are describedwith respect to the 4 GHz portion of the C-band, as well as the 6 Ghzspectrum; however, the systems and methods described herein are furtheradvantageously adaptable to provide similar functionality for otherspectral ranges that are utilized in communication systems that utilizethe same, or similar, conventional system components (e.g., earthstations, satellite dishes, transmitters, receivers, APs, UEs, etc.),and/or are capable of being equipped with some or all of the beacontransmission/detection infrastructure described throughout thisapplication.

In an embodiment, FSS site includes one or more of each ofplatform-mounted beacon receiver 1904, station-integrated beaconreceiver 1906, co-located beacon receiver 1908, and auxiliary beaconreceiver 1910. In the exemplary embodiment depicted in FIG. 19, earthstation 1902(1) includes platform-mounted beacon receiver 1904, earthstation 1902(2) includes station-integrated beacon receiver 1906, earthstation 1902(3) includes a single co-located beacon receiver 1908, andearth station 1902(4) includes a plurality of co-located beaconreceivers 1908. In this example, FSS site 1900 further includes aplurality of auxiliary beacon receivers 1910, which may be similar todistributed detector 548, FIG. 5.

FSS site 1900 thus represents a distributed beacon receiver system,where the several beacon receivers 1904, 1906, 1908, 1910 aredistributed at or among earth stations 1902 to capture beacontransmission signals from remote beacon transmitters 1912 and reportinformation, such as the beacon power, beacon ID, and the status of therespective beacon receiver to central server 1914 to enable centralserver 1914 to estimate the potential interference. According to thisadvantageous embodiment, the potential interference may be estimatedboth at the single FSS site 1900, and also at all FSS sites within rangeof a beacon-transmitting AP. Through implementation of this advantageousinfrastructure, central server 1914 is further capable of coordinatinginterference-free FSS operation across all of the FSS sites withinrange. In exemplary implementation, a particular beacon receiver may bedisposed with respect to earth station 1902 of FSS site 1900 by (i)mounting (e.g., platform-mounted beacon receiver 1904), (ii) integrating(e.g., station-integrated beacon receiver 1906), (iii) co-locating(e.g., co-located beacon receivers 1908), and/or (iv) auxiliaryplacement (e.g., auxiliary beacon receivers 1910).

FIG. 20 is a schematic illustration of a beacon detection system 2000that implements earth station 1902(1) and platform-mounted beaconreceiver 1904, FIG. 19. Platform-mounted beacon receiver 1904 is anoptional, or supplemental, configuration to the several beacon receiverconfigurations described herein (e.g., beacon receivers 1906, 1908,1910). According to beacon detection system 2000, platform-mountedbeacon receiver 1904 may be directly mounted to a fixed component ofearth station 1902(1). In the exemplary embodiment, platform-mountedbeacon receiver 1904 is fixed to earth station 1902(1) at a positionproximate an antenna feed socket 2002 (i.e., near the focal point of areflector 2004). From this exemplary location, platform-mounted beaconreceiver 1904 is able to share the antenna gain, and thus also thereceived power, similar to the respective gain and power that will beobserved at a feed horn 2006. Feed horn 2006 may be, in this example,similar to feed horn 208, FIG. 2. In this example, platform-mountedbeacon receiver 1904 is similar to integral beacon detector 528(1), FIG.5.

According to one or more of the calibration techniques described above,platform-mounted beacon receiver 1904 is able to measure the beacon andassociated potential interference level approximate to a level at areference point 2008 between an RRF 2010 and an LNB 2012.

In exemplary operation of beacon detection system 2000, the power levelP_(ref) (in dB) may be calculated at reference point 2008 according to:

P _(ref) =P _(BR) +P _(cal)   (Eq. 1)

where P_(BR) represents the measured power at platform-mounted beaconreceiver 1904 with an equivalent isotropic antenna and a 0-dB gain, andP_(cal) represents a calibration factor. In exemplary operation, eachplatform-mounted beacon receiver 1904 is configured to submit themeasured data, including, for example, P_(ref) and/or P_(BR), satelliteantenna gain (or dish parameters), and/or the FH or RRF losses to thecentral server (e.g., central server 1914, FIG. 19), that is, in somecases, P_(ref) represents a sum of P_(BR)+P_(BR-measured), whereP_(BR-measured)=P_(BR)+Gain_(reflector).

FIG. 21 is a schematic illustration of a beacon detection system 2100that implements earth station 1902(2) and station-integrated beaconreceiver 1906, FIG. 19. In this example, station-integrated beaconreceiver 1906 represents an alternative embodiment of integral beacondetector 528(1), FIG. 5. In an embodiment, implementation ofstation-integrated beacon receiver 1906 at a particular earth station1902 (e.g., earth station 1902(2)) advantageously enables protection ofthe particular FSS site without additionally requiring implementation ofplatform-mounted beacon receiver 1904, co-located beacon receiver 1908,or auxiliary beacon receiver 1910.

According to beacon detection system 2100, station-integrated beaconreceiver 1906 is tapped into a link 2102 between an LNB 2104 and asatellite signal receiver 2106. Through this integration ofstation-integrated beacon receiver 1906 into link 2102, a measurementmay be obtained which includes the exact antenna gain and the linkattenuation before a reference point 2108. According to this exemplaryarchitecture, the hardware design of station-integrated beacon receiver1906 may be greatly simplified in comparison with directly-mounteddesigns, because the sensitivity requirements of the receiver weresignificantly relieved due to the ability to share components, such asLNB 2104. In an embodiment, beacon detection system 2100 furtherincludes an RRF 2110 and a feed horn 2112. In at least one embodiment,this configuration is realized through utilization of a spare LNB thatis not presently in use by system 2100, or alternatively, throughinstallation of a large LNB array.

In exemplary operation of beacon detection system 2100, the power levelP_(ref) may be calculated at reference point 2108 according to:

P _(ref) =P _(BR) −G _(LNB) +A   (Eq. 2)

where G_(LNB) represents the gain of LNB 2104, and A represents theattenuation and insertion loss of a portion 2114 of link 2102 betweenLNB 2104 and station-integrated beacon receiver 1906. In exemplaryoperation, each station-integrated beacon receiver 1906 is configured tosubmit the measured data, including, for example, P_(ref), P_(BR), thesatellite antenna gain (or dish parameters), and/or FH and RRF losses tothe central server (e.g., central server 1914, FIG. 19).

In the exemplary embodiment depicted in FIG. 21, station-integratedbeacon receiver 1906 is illustrated to be disposed after LNB 2104 (i.e.,with respect to each particular dish utilizing beacon receiver 1906),but before satellite signal receiver 2106, and tapped at link 2102.Through this advantageous configuration, station-integrated beaconreceiver 1906 is capable of directly measuring the interference at theparticular dish (or each utilizing dish). The received beacon signalwill thus directly experience the same satellite antenna gain as willthe signal for any direction. This advantageous configuration wouldrequire little or no calibration, and may be simply installed withrespect to existing conventional infrastructures through use of a tapafter LNB 2104, and would therefore involve no significant interruptionto the service by this type of installation. Other types of beaconreceiver configurations may individually vary with respect to theaccuracy of measurements, the cost of installation, and the requiredcalibration, but may nevertheless provide particular advantagesdepending on the actual considerations experience that an individual FSSsite.

In some embodiments, at least one steerable beacon detector is disposedexternally to an FSS site, and may operate as a single beacon receiverfor several dishes at the particular site, aunt/or for other siteswithin the operational range. In this example, the steerable beacondetector may be configured to have a higher antenna gain than the FSSsite itself, particularly in the case of small diameter dishes beingused at the FSS site. In practice, conventional 2-m dishes have highgains of approximately 37 dBi, which is generally higher than the gainof such an external steerable antenna. Nevertheless, the presentembodiments contemplate utilizing higher-gain narrow-beam antennas toincrease the link budget for beacon detection, which may be steerable,for example, using MIMO.

Although use of such external beacon receivers might increase the costor complexity of the overall system in some other respects, the externalbeacon receivers may simultaneously also increase the size of theoverall sensor network for interference measurements for calculations tobuild and improved the MBP models of the central server. Nevertheless,other APs may also include their own beacon detectors, thereby providingan alternative (or supplemental) technique to increase the size of thissame sensor network.

Referring back to FIG. 19, co-located beacon receivers 1908 representsan alternative, or supplemental in some embodiments, configuration intoeither or both of beacon detection system 2000, FIG. 20, and beacondetection system 2100, FIG. 21. As illustrated in FIG. 19, co-locatedbeacon receivers 1908 are disposed adjacent to, but not connecteddirectly with, and antenna system (not separately shown) of therespective earth station (e.g., earth stations 1902(3), 1902(4)). In atleast one embodiment, one or more of beacon receivers 1908 are installedoutside of the boundaries of the particular the FSS site, to obtainadditional information for the MBP-based propagation model. According tothis exemplary configuration, co-located beacon receivers 1908 may beindividually steered toward a direction and position similar to theantenna of the earth station, such that an individual co-located beaconreceiver 1908 may emulate a spatial response similar to that of theantenna.

In some embodiments, steerable antennas having narrow-beam and high-gainfunctionality are utilized to detect beacons instead of (or in additionto) the radar system infrastructures described herein. For example, therespective satellite dishes of such steerable antennas may enableincreases to the link budget for the beacon detection system, due to thehigher gains thereof. In one example, each FSS site may include at leastone steerable antenna per site, and the central server thereof may befurther configured to build and dynamically update a model based on theinter-detected beacon interference to each FSS at the particular FSSsite.

In exemplary operation, co-located beacon receivers 1908 are configuredsuch that the power level P_(ref) at reference point (not shown withrespect to co-located beacon receiver 1908) of the respective earthstation 1902(3), 1902(4) may be calculated or estimated according to:

P _(ref) =P _(BR) +G _(ant)(θ)−0.5   (Eq. 3)

where G_(ant)(θ) represents the measured antenna gain (in dB) of theantenna of the respective earth station 1902(3), 1902(4) in thecorresponding direction θ of the detected beacon transmitter (e.g.,beacon transmitter 1912, FIG. 19), and where P_(BR) is expressed in dBmand the 0.5 value represents an RRF loss of 0.5 dB. In the exemplaryembodiment, the direction θ is determined from the respective locationsof the beacon transmitters and earth station 1902(3) or 1902(4). In someembodiments, the direction θ may be affected by the elevation andazimuth angles of earth station 1902(3) or 1902(4). In an embodiment, anominal value for antenna gain G_(ant)(θ) may also be calculated, e.g.,according to FCC § 25.209(a), if the actual measured data of the antennais unavailable. In at least one embodiment, the measured value P_(BR)is, for example, an average value, or may represent a combination ofmeasured values from multiple co-located beacon receivers 1908 where aplurality are disposed proximate an individual earth station, such asearth station 1902(4). In at least one embodiment, the measured valueP_(BR) is obtained using a high-gain antenna.

Similar to the embodiments described above with respect to beacondetection systems 2000, 2100, each co-located beacon receiver 1908 maybe configured to submit the measured data, including, for example, thesingle or combination value for P_(ref) and/or P_(BR), to the centralserver (e.g., central server 1914, FIG. 19).

With reference to Eq. 3, above, the calculated power level might deviatefrom the true level at the respective reference point. In such cases,this deviation may not be possible to correct through calibrationtechniques, due to the physical separation between co-located beaconreceiver 1908 and the respective earth station 1902(3) or 1902(4), andthe associated variation and uncertainty of the power level over space.Such variation and uncertainty might be particularly severe at earthstation sites that include metallic facilities sufficient to causestrong multi-path effects and/or power fading. Where such difficultiesare encountered, the systems and methods described herein may be furtheradvantageously configured to deploy one or more auxiliary beaconreceivers 1910 throughout FSS site 1900, or to implement a simplifiedconfiguration at each individual dish according to system 2100.

Therefore, according to this exemplary auxiliary configuration, aplurality of auxiliary beacon receivers 1910 may be distributedthroughout FSS site 1900 and function to advantageously provideadditional, but separate, measured samples for estimating the powerlevels at earth stations 1902 equipped with a mounted, an integrated,and/or a co-located detector. In the exemplary embodiment, auxiliarybeacon receivers 1910 further serve to function to provide a power levelestimate for an earth station that does not include its own beacondetector, or at least one of the mounted, integrated, or co-locatedembodiments described above.

In at least one embodiment, a plurality of auxiliary beacon receivers1910 are disposed such that they surround earth stations 1902 at variousand/or random locations where power and/or an Internet connection isavailable, but which may not be readily available or easily accessed bya particular earth station 1902. Through this advantageousconfiguration, earth stations 1902 may located and positioned to receiveoptimal satellite transmission signals, even if such locations are notoptimal to measure potential interference or communicate with thecentral server.

In exemplary operation of auxiliary beacon receivers 1910, the powerlevel P_(ref) at reference points of respective earth stations 1902 maybe calculated in several ways. In a first example, a maximal valuemax{P_(BR,i)} is selected from data obtained from co-located beaconreceivers 1908 and a subset of the surrounding auxiliary beaconreceivers 1910 within a predetermined range, according to:

P _(ref)=max{P _(BR,i) }+G _(ant)(θ)−0.5   (Eq. 4)

In a second example, the power level P_(ref) is obtained using the meanof the power collected from these co-located beacon receivers 1908 andauxiliary beacon receivers 1910, with a total number of N, according to:

$\begin{matrix}{P_{ref} = {{\frac{1}{N}{\sum\limits_{i}^{N}{c_{i}P_{{BR},i}}}} + {G_{ant}(\theta)} - 0.5}} & \left( {{Eq}.\mspace{14mu} 5} \right)\end{matrix}$

where c_(i) represents a coefficient for the i-th beacon receiver, inthe case where different beacon receivers have different weights. In anembodiment, the coefficient c_(i) may be derived from a previouscalibration and/or training techniques during operation.

In a third example, the power level P_(ref) is obtained usinginterpolation, e.g. Kriging interpolation, based on the location andelevation of the earth station antenna, as well as the respective powerlevels, locations, and elevations of a subset of the surroundingauxiliary beacon receivers 1910 within the predetermined range. Similarto the embodiments described above, each auxiliary beacon receiver 1910may also be configured to submit the measured data, including, forexample, its own P_(BR), to the central server (e.g., central server1914, FIG. 19). Alternatively, an individual auxiliary beacon receivers1910 is configured to submit data to a different auxiliary beaconreceiver 1910 belonging to the same subset, and this different auxiliarybeacon receiver 1910 may then submit the combined result P_(ref) to thecentral server.

FIG. 22 is a schematic illustration of a distributed antenna system(DAS) 2200 configured to implement protection scheme 400, FIG. 4. In theexemplary embodiment, DAS 2200 may be deployed in addition, or as analternative, to each of the four embodiments of beacon receivers 1904,1906, 1908, 1910 described above. That is, the at least one embodiment,DAS 2200 is deployed as a substitute for the distributed beacondetection architectures described above.

In an exemplary embodiment, DAS 2200 includes a central beacon receiver2202 and a plurality of remote antennas 2204 distributed throughout anFSS site (e.g., FSS site 502, FIG. 5), with each remote antenna 2204having at least one operable communication connection with centralbeacon receiver 2202. In some embodiments, DAS 2200 further includes oneor more remote beacon receivers 2206, according to the embodimentsdescribed above. In exemplary operation, central beacon receiver 2202collects received signals from remote antennas 2204, and may be furtherconfigured to derive the power level P_(BR) that applied onto therespective reference point of an earth station 2208.

In a first example, the power level P_(BR) is obtained by selecting themaximal value max{P_(ant,i)} from the plurality of remote antennas 2204,according to:

P_(BR)=max{P_(ant,i)}  (Eq. 6)

where P_(ant,i) represents the measured power at the i-th remote antenna2204 with an equivalent isotropic antenna and a 0-dB gain over the linkof DAS 2200.

In a second example, the power level P_(BR) is obtained using the meanof the power collected from a total number M of remote antennas 2204,according to:

$\begin{matrix}{P_{BR} = {\frac{1}{M}{\sum\limits_{i}^{M}{d_{i}P_{{ant},i}}}}} & \left( {{Eq}.\mspace{14mu} 7} \right)\end{matrix}$

where d_(i) represents a coefficient for the i remote antenna 2204.Similar to coefficient c_(i), described above, the coefficient d_(i) mayalso be derived from a previous calibration and/or training techniquesduring operation. In further operation of DAS 2200, the results obtainedfrom Eq. 6 or Eq. 7 are applied to the calculation represented by Eq. 3to derive the power level at the respective reference point.

The advantageous configuration of DAS 2200 realizes further benefits ofbeing able to implement conventional DAS schemes with respect to theinnovative beacon detection and decoding embodiments described herein.In an exemplary operation, a maximal ratio combining (MRC) mechanism isused upon signals from remote antennas 2204 before correlating a subjectbeacon ID from a particular beacon transmitter j (e.g., beacontransmitter 1912, FIG. 19), according to:

$\begin{matrix}{x_{{BR},j} = \frac{\sum\limits_{i}^{N}{h_{i,j}*x_{i}}}{\sum\limits_{i}^{N}{h_{i,j}}^{2}}} & \left( {{Eq}.\mspace{14mu} 8} \right)\end{matrix}$

where x_(i) represents a signal vector collected at the i remote antenna2204, h_(i,j) represents a channel response from the j beacontransmitter to the i remote antenna 2204, and estimated using a prioriinformation, or from a previous measurement. The derivation valuex_(BR,j) may then be used for succeeding receiver processing, such ascorrelation with the reference beacon signal from the j beacontransmitter. In the exemplary configuration of DAS 2200, each of remoteantennas 2204, as well as RF filters or related components (not shown)are implemented to follow the relevant descriptions in FCC part 25 andpart 96. In each of the foregoing embodiments, the individual techniquesand configurations of the several different beacon detectionalternatives (i.e., mounted, integrated, co-located, auxiliary, DAS) maybe advantageously implemented alone, or in any combination with each ofthe other alternatives.

Directional and Multi-Antenna Systems for in-band Protection

The present embodiments are further of particular advantageous use withrespect to the operation of directional-antenna and multiple antenna(also referred to herein as “multi-antenna”) mobile communicationsystems, and specifically for minimizing the interference to and fromsatellite systems that operate in the same or adjacent frequency band.The following embodiments may be employed with one or more of the beacontransmission systems and methods described above, whether in whole or inpart.

As described above, mobile communication systems presently coexist withsatellite communication systems in the same CBRS band. Some recentmobile communication proposals seek to liberate spectrum for flexibleuse within the 3.7-4.2 GHz, 5.925-6.425 GHz, and 6.425-7.125 GHz bands.The 3.7-4.2 GHz band, for example, includes 12 channels on eachpolarization, which are primarily used for the downlink (i.e., fromspace to earth) of satellite communication systems. There are thousandsof earth stations operating in this band in the US, and these earthstations require interference protection. At present, the FCC regulatesthe interference levels from services sharing the same band.Interference considerations may not be the same in the 6 GHz bandsthough, since the satellite uplink does not have the sensitivity of thedownlink. Nevertheless, very close proximity that is typically seenbetween satellite transmitters may still give rise to particularprotection needs.

Macro-cellular deployment for mobile use within these spectra willgenerally create interference to FSS sites that use the C-band downlink,due to the lower propagation loss above clutter (i.e., relative to belowclutter), as well as from the use of significantly higher transmitterpowers in comparison with that of small cell use. At present, theprotection distances between a macrocell and an FSS site tend to beconsiderably large, and exacerbated by MIMO antenna implementations,which effectively enhance the gain of the base station and increase thespectral density thereof. The present systems and methods mitigate theseobstacles considerably in mobile use cases, as described herein.Nevertheless, some of these embodiments may be of even furtheradvantageous use with respect to fixed wireless access (FWA)implementations in light of the speed of beam-forming across a mobilenetwork. In some countries, the use of the 3.7-4.2 GHz spectrum isconfined to limited geographical regions without widespread distributionof FSS. In such cases, it may be more desirable to allow use of theC-band for mobile implementations, and fixed radio use elsewhere. Insome of these cases, however, interference may still occur in boundaryregions between these geographical areas, in which case a buffer regionmay be created between the two usage systems (e.g., minimized to enhancemicrocellular mobile coverage).

Multi-antenna technologies, such as MIMO and massive MIMO, are known toincrease spectral efficiency by providing multiplexing gain, and toimprove SNR by providing diversity gain. Multi-antenna and technology istherefore of particular utility with respect to emerging communicationtechnologies, such as 5G. Multi-antenna systems support multipleusers/multi-user, as well as high-resolution beamforming (sometimeslabeled as “BF”). Beamforming is conventionally implemented in existingcommunication standards, such as coordinated multipoint (CoMP) in LTEfor interference mitigation. Multi-antenna transmission is considered tobe capable of maximizing the power level at a particular location bybeamforming techniques, or minimizing the power level by the relatednull forming (sometimes labeled as “NF”) techniques.

With respect to FWA implementations using the 3.7-4.2 GHz C-band, suchas in 5G, MIMO-based systems may be particularly useful in rural areas,where the density of surrounding FSS sites would be expected to beconsiderably lower than it would be in higher populated areas. With FWAspecifically, the number of connected locations is expected to besignificantly lower than with a mobile use case.

As also described above, conventional coexistence techniques do not usethe beacon infrastructure described herein, and are primarily based onpropagation modeling, priority tiers, protection zones, and radiosensing. As described further below, the present systems and methods maybe advantageously configured to implement an innovative auxiliary beaconinfrastructure onto even conventional mobile communication systems. Thepresent embodiments are thus further capable of being configured to usedirectional and multi-antenna technology, and also implementadvantageous techniques that enable greater control of the signalpattern radiated from (or received at) the particular mobilecommunication system. This radiated signal pattern may then be managedto cause minimal interference at the satellite system/mobilecommunication system, thereby reducing the protection distance betweenthe system and the FSS site. This consideration could be particularlyuseful, for example, where it is desirable to reduce the size of thebuffer area or where there is a low density of FSS sites surrounding amacrocell size.

FIG. 23 is a schematic illustration of a multiple-antenna shared-usesystem 2300. Shared-use system 2300 may include, or be utilized in acomplementary fashion with, one or more of the several embodimentsdescribed above. In an exemplary embodiment, shared-use system 2300includes an earth station 2302 and a plurality of UEs 2304 (e.g., orfixed transceivers, as in the case of FWA) in proximity one or both of afirst antenna system 2306 and a second antenna system 2308. In theexample depicted in FIG. 23, first antenna system 2306 represents acommunication system AP (e.g., mobile, FWA, etc.) equipped with amulti-antenna wireless transceiver, and second antenna system 2308represents a communication system AP equipped with a directionalantenna.

In one embodiment, such as an FWA use case where an FSS site is locatedbehind a receiving home direction, use of a null might disconnect thislocation. In such cases, a MESH network interconnecting homes, may beimplemented in a cooperative manner with the present embodiments, thuslowering the number of communication links.

In exemplary operation of system 2300, first antenna system 2306generates a first beam pattern 2310, and second antenna system 2308generates a second beam pattern 2312. As depicted in FIG. 23, first beampattern 2310 from the multi-antenna transceiver of first antenna system2306 radiates one or more spatial radio beams (also referred to hereinas beamforming, or BF, herein) 2314 for spatial high-gain UE or FWAcoverage (e.g., UEs 2304(1), 2304(2)), while forming a null 2316 (alsoreferred to as null forming, or NF, herein) to mitigate radiation in afirst direction 2318 toward earth station 2302. In contrast, second beampattern 2312 from the directional antenna of second antenna system 2308is more uniform and generates minimal radiation in a second direction2320 toward earth station 2302.

FIG. 24 illustrates a far field beam pattern 2400 for a multiple antennasystem 2402. Far field beam pattern 2400 is similar to first beampattern 2310, FIG. 23, of first antenna system 2306, except thatmulti-antenna system 2402 is configured to utilize beamforming toradiate a plurality of radio beams (BFs) 2404 in multiple directionsabout multiple antenna system 2402, such that beam pattern 2400 resultsin the far field shape depicted in FIG. 24.

FIG. 25 is a schematic illustration of a multiple antenna system 2500.System 2500 includes at least one multi-antenna transceiver array 2502and a field beam pattern 2504 radiating a plurality of high-gain radiobeams 2506 toward respective UEs 2508 or FWA transceivers. FIG. 26 is aschematic illustration of a multiple antenna system 2600. System 2600includes at least one multi-antenna transceiver array 2602 and a fieldbeam pattern 2604 which forms a plurality of nulls 2606 directed towardrespective earth stations 2608. Earth stations 2608 may be similar toearth station 2302, FIG. 23. Multi-antenna transceiver 2602 may besimilar in structure to multi-antenna 2502, FIG. 5.

Conventional coexistence technology utilizes BF to provide bettercoverage for UE sets (e.g., FIG. 25), or to minimize the interferenceinside the mobile network of system 2500. The innovative systems andmethods described herein though, are additionally configured andprogrammed to further operate the respective antenna arrays to providethe plurality of nulls 2606 toward and/or from respective earth stations2608 (e.g., FIG. 26), and also to extend the use case to FWA. Theunderlying structures and operations of systems 2500 and 2600 aredescribed further below with respect to various combinations thereof inthe following multiple antenna systems. In the following embodiments,the various UEs are depicted for illustration purposes to representrespective mobile communication subsystems or FWA transceivers, andvarious earth stations are depicted for similar purposes, namely, torepresent respective satellite subsystems.

FIG. 27 is a schematic illustration of a multiple antenna system 2700.Similar to FIGS. 25 and 26, above, system 2700 also includes at leastone multi-antenna transceiver array 2702 configured to generate a beampattern 2704. Unlike conventional systems, multi-antenna transceiverarray 2702 may be advantageously configured to generate a far field beampattern 2706, and also to implement both BF and NF. In some cases, array2702 implements BF and NF simultaneously. In the exemplary embodiment,beam pattern 2704 includes a plurality of high-gain radio beams 2706directed toward a plurality of mobile subsystems 2708 (e.g., includingUEs), respectively. In a similar, but complementary, manner, beampattern 2704 further includes a plurality of nulls 2710 directed towardrespective satellite subsystems 2712 (e.g., including earth stations).

In exemplary operation of system 2700, array 2702 is configured toimplement both BF and NF to protect a satellite downlink 2714 tosatellite subsystems 2712 from a mobile downlink 2716 of mobilesubsystems 2708. That is, in order to protect satellite downlink 2714from mobile downlink 2716, operation of array 2702 is configured toestablish both BF and NF at substantially the same time for transmissionof mobile downlink 2716 in a cell (e.g., beam pattern 2704) covered bymultiple antenna system 2700. In the exemplary embodiment, beams 2706and nulls 2710 are generated from the same mechanism (e.g., a centralprocessor (not shown) cooperating with array 2702). According to thisexample, using the MBP techniques described above, the respective beams2706 and nulls 2710 may be further optimized for both improved UE/FWAcoverage and satellite protection. In a case where transmission of abeacon from a base station is problematic, one contemplated remedy wouldbe a change in the frequency of operation.

In at least one embodiment of system 2700, the BF and NF operations mayeach further consider the channel status and system information. Forexample, as illustrated in FIG. 27, the satellite subsystem farthestfrom array 2702 (satellite subsystem 2712(1) in this example) mayrequire less NF attenuation than a satellite subsystem farther away(satellite subsystem 2712(2) in this example), as indicated by null2710(1) being substantially smaller than null 2710(2). This use case maybe particularly advantageous, for example, in FWA and 5Gimplementations.

In one example of system 2700, the base station may be on the samefrequency as the satellite ground station. In such cases, system 2700may be implemented in a complementary fashion with a stoplight system,e.g., stoplight system 3800, FIG. 38 (described further below) to morereliably eliminate significant interference at the ground stations witha means of identification. A stoplight system may further serve toimprove the successful implementation of the MBP techniques describedabove. Nevertheless, according to the BF and NF principles of system2700, the base station location may be significantly closer thanconventionally seen, thus enabling better coverage and capacity withinthe cellular network.

FIG. 28 is a schematic illustration of a multiple antenna system 2800.System 2800 may be similar to system 2700, FIG. 27, in overallarchitecture and general functionality. That is, system 2800 may includeat least one multi-antenna transceiver array 2802 configured to generatea beam pattern 2804 implementing at least BF, and including a pluralityof beams 2806 respectively directed toward a plurality of mobilesubsystems 2808. System 2800 differs from system 2700 though, in thatsystem 2800 illustrates a case for protecting a respective satellitedownlink 2810 of a satellite subsystem 2812 from a mobile uplinktransmission 2814 from one or more of mobile subsystems 2808. In thisexemplary embodiment, as well as the several following embodiments,“mobile” may be considered to refer to both mobile and FWA transceivers.

More particularly, in exemplary operation of system 2800, beamforming isestablished for mobile/FWA uplink transmission 2814 within the cellcovered by beam pattern 2804, such that the SNR in the uplink fromrespective UEs or FWA transceivers of mobile subsystem(s) 2808 may beadjusted and/or optimized at a receiver portion (not separately shown)of multi-antenna transceiver array 2802 using a minimal transmittedpower from the respective UEs. It may be noted in this particularexample, that because protection is only sought for satellite downlink2810 from mobile uplink transmission 2814, it is not necessary toconsider NF techniques for forming nulls in this particular embodiment.

FIG. 29 is a schematic illustration of multiple antenna system 2900. Inthe exemplary embodiment, system 2900 is similar to system 2700, FIG.27, in architecture and functionality, and may include at least onemulti-antenna transceiver array 2902 configured to generate a beampattern 2904 implementing both BF and NF, which includes a plurality ofbeams 2906 respectively directed toward a plurality of mobile subsystems2908, as well as a plurality of nulls 2910 directed toward respectivesatellite subsystems 2912. System 2900 differs from system 2700 though,in that system 2900 illustrates a case for minimizing interference to amobile uplink transmission 2914 of mobile subsystems 2908 from arespective satellite uplink 2916 of one or more satellite subsystems2912.

More particularly, in exemplary operation of system 2900, both BF and NFare established in the cell covered by multi-antenna transceiver array2902 for mobile uplink transmission(s) 2914 within the cell. In at leastone embodiment of system 2900, the BF and NF operations may each furtherconsider the channel status and system information, similar to system2700, FIG. 27. Also similar to system 2700, as illustrated in theexample depicted in FIG. 29, the satellite subsystem farthest from array2902 (satellite subsystem 2912(1) in this example) may require less NFattenuation than a satellite subsystem farther away (satellite subsystem2912(2) in this example), as indicated by a first null 2918 beingsubstantially smaller than a second null 2920.

FIG. 30 is a schematic illustration of a multiple antenna system 3000.System 3000 may be similar to system 2800, FIG. 28, in architecture andfunctionality. That is, system 3000 may include at least onemulti-antenna transceiver array 3002 configured to generate a beampattern 3004 implementing at least BF, which includes a plurality ofbeams 3006 respectively directed toward a plurality of mobile subsystems3008. System 3000 differs from system 2800 though, in that system 3000illustrates a case for minimizing interference to a mobile downlinktransmission 3010 to mobile subsystems 3008 from a respective satelliteuplink 3012 of one or more satellite subsystems 3014.

More particularly, in exemplary operation of system 3000, beamforming isestablished for mobile downlink transmission 3010 within the cellcovered by beam pattern 3004, such that the downlink SNR frommulti-antenna transceiver array 3002 may be maximized at the respectiveUEs of mobile subsystems 3008. It may be noted in this particularexample, that because protection is only sought for mobile downlink 3010from satellite uplink transmission 3012, it is not necessary to considerNF techniques for forming nulls in this particular embodiment.

FIG. 31 is a schematic illustration of a mobile network 3100implementing joint beamforming and null forming. In an exemplaryembodiment, mobile network 3100 includes at least one satellitesubsystem 3102, at least one mobile subsystem 3104, a first multipleantenna communication cell 3106 (CELL #1), and a second multiple antennacommunication cell 3108 (CELL #2). Each of first and secondcommunication cells 3106, 3108 may be similar to the cells described inthe embodiments above, and include at least one respective multi-antennatransceiver array 3110, each of which may be configured to implementboth BF and NF.

In an exemplary operation of mobile network 3100, BF and NF areestablished based on the global condition of mobile network 3100, andjointly managed according to the innovative techniques described herein.That is, in practice, a plurality of multi-antenna communication systems(e.g., first and second communication cells 3106, 3108) may jointlyprovide desired coverage for one or more UEs or FWA transceivers ofmobile subsystem 3104, while also providing protection to (and from)satellite subsystem(s) 3102. In this embodiment though, the jointoperation of cells 3106, 3108 is configured to manage the operation ofeach cell in consideration of the other cell.

For example, as depicted in FIG. 31, joint operation of cells 3106, 3108may initially establish NF for each cell in regard to the other. In thisexample, in a direction of second cell 3108, first cell 3106 forms afirst null 3112 in a first beam pattern 3114 of first cell 3106.Similarly, in a direction of first cell 3106, second cell 3108 forms asecond null 3116 in a second beam pattern 3118 of second cell 3108. Ajoint effect of first and second nulls 3112, 3116 between the respectivecells 3106, 3108 serves to minimize inter-cell interferencetherebetween. In further operation of system 3100, first cell 3106 isconfigured to additionally form a third null 3120 in first beam pattern3114 in the direction of satellite subsystem 3102, and second cell 3108is configured to additionally form a fourth null 3122 in second beampattern 3118, also in the direction of satellite subsystem 3102.

In this example, because the second cell 3108 is depicted to be fartheraway from satellite subsystem 3102 than is first cell 3106, fourth null3122 is illustrated to be somewhat smaller than third null 3120,signifying a lower need for attenuation due to increased distance frompotential interference. In still further operation of system 3100, firstcell 3106 is additionally configured to establish BF toward mobilesubsystem 3104, despite the existence of mobile subsystem 3104 (e.g., aUE thereof) between first cell 3106 and second cell 3108. That is, inthe direction of mobile subsystem 3104, first cell 3106 generates aradio beam 3124. In at least one embodiment, first cell 3106 generatesradio beam 3124 toward mobile subsystem 3104 even in the case where a UEof mobile subsystem 3104 is physically located within the transmissionboundaries of second cell 3108.

Accordingly, in the example depicted in FIG. 31, it can be seen thatfirst null 3112 and radio beam 3124 in beam pattern 3114 distorted shapeto beam pattern 3114 where null 3112 is superimposed with beam 3124.Similarly, it can be seen that second null 3116 and fourth null 3122also form a distorted shape in beam pattern 3118 from thesuperimposition thereof. As described above, this effect may bedifferent for mobile UEs (e.g., in a fast-moving vehicle), as comparedwith a fixed transceiver of an FWA subsystem. System 3100 is depicted,for ease of illustration, with respect to a satellite downlink 3126 ofsatellite subsystem 3102 and a mobile downlink transmission 3128 fromarray 3110(1) of first cell 3106 to mobile subsystem 3104. However, theperson of ordinary skill in the art will understand that the principlessystem 3100 fully apply also in the case of a satellite uplink and/ormobile uplink, as described above in the preceding embodiments.

Through the innovative BF and NF techniques of system 3100 describedherein, the respective superimposed pattern shapes of the cells may beoptimized to achieve particular benefits over conventional systems,including without limitation: (1) maximal SNR, from the respective UEs,at the receiver (not shown in FIG. 31) of multi-antenna transceiverarray(s) 3110; (2) maximal SNR, at the UEs/FWA transceivers, frommulti-antenna transceiver array(s) 3110; (3) minimal power, frommulti-antenna transceiver array(s) 3110 and the UEs of mobilesubsystem(s) 3104, at nearby satellite subsystems 3102; and (4) minimalpower, at multi-antenna transceiver array(s) 3110 and the UEs of mobilesubsystem(s) 3104, from nearby satellite subsystems 3102. In anexemplary embodiment, operation of system 3100 is configured to optimizeone or more of the preceding benefits according to predeterminedcriteria of the particular system, and may prioritize realization of onesuch benefit over another.

FIGS. 32A-C are schematic illustrations of a mobile network 3200configured to implement dynamic null forming for different respectivefrequencies. In an exemplary embodiment, mobile network 3200 includes atleast one multi-antenna transceiver array 3202 generating a beam pattern3204. Beam pattern 3204 includes a first null 3206 in a direction of afirst satellite subsystem 3208 and a second null 3210 in a direction ofa second satellite subsystem 3212. In exemplary operation of mobilenetwork 3200, array 3202 is configured to implement dynamic NF inaccordance with changing frequency channels transmitted by first andsecond satellite subsystems 3208, 3212. According to this dynamic NFtechnique, mobile network 3200 is configured to optimally change theshape of beam pattern 3204 to provide a dynamic protection pattern. Insome embodiments, network coordination and signaling are optimized toaddress latency concerns, and also with respect to the beacontransmissions described above.

More particularly, according to the present embodiments, BF and NF mayboth be established subject to the actual status of the respective UEsor mobile/FWA transceiver subsystems, satellite subsystems (e.g.,subsystems 3208, 3212), and the respective channels operated thereby. Asillustrated above, that is, through a comparison of FIGS. 32A, 32B, and32C, the NF shape of beam pattern 3204 changes over time as thefrequency channels of the respective satellite subsystems 3208, 3212change. In at least one embodiment, in the case of a fast-moving UE(e.g., a mobile phone in a moving automobile), the system may beconfigured to move the particular device to a different band.

Specifically, in this example, first and second nulls 3206 _(A) and 3210_(A) have an initial shape when first and second satellite subsystems3208, 3212, respectively, are at initial frequency channels, as depictedin FIG. 32A. As depicted in FIG. 32B, when the frequency channel changesfor second satellite subsystem 3212′, the shape of second null 3210 _(E)also changes in time in accordance with the respective frequency change.In this example, the frequency channel of first satellite subsystem 3208has not changed, and therefore there is no corresponding change to theshape of first null 3206 (i.e., the shape of first null 3206 _(B) issubstantially the same as the shape of first null 3206 _(A)). Asdepicted in FIG. 32C, when the frequency channel changes for firstsatellite subsystem 3208′, the shape of first null 3206 _(C) alsochanges in time (from the shape of null 3206 _(B)). In this examplethough, the frequency channel of second satellite subsystem 3212′ hasnot changed from the example of FIG. 32B, and therefore there is nofurther corresponding change to the shape of second null 3210 based onlyon the change in the shape of first null 3206 (i.e., the shape of secondnull 3210 _(c) is substantially the same as the shape of second null3210 _(B)).

FIG. 33 is a schematic illustration of a mobile or FWA network 3300implementing channel estimation. In an exemplary embodiment, mobilenetwork 3300 includes at least one multi-antenna transceiver array 3302generating a beam pattern 3304. Beam pattern 3304 includes a pluralityof nulls 3306 respectively formed in directions of a plurality ofsatellite subsystems 3308. In this example, beam pattern 3304 furtherincludes a plurality of radio beams 3310 respectively formed indirections of a mobile or FWA subsystems 3312. In the exemplaryembodiment, each of satellite subsystems 3308 is equipped with a radiosensor 3314 (e.g., a beacon detector, as described above) within an FSSsite of the respective subsystem 3308, or in operable communicationtherewith, in accordance with one or more of the embodiments describedabove (e.g., co-located, integrated, etc.).

In exemplary operation of mobile network 3300, a transmitter (notseparately shown) of multi-antenna transceiver array 3302 is configuredto transmit a training symbol or beacon. In some embodiments, thesetransmitted symbols/beacons are sent at a relatively low power level, asdescribed with respect to the beacon infrastructure systems and methodsabove, and optionally may or may not include information pertaining tothe location of the respective satellite subsystem 3308, and/or nulls3306 formed using NF. Respective sensors 3314 are configured to becapable of detecting the transmitted training symbol(s)/beacon(s),thereby enabling mobile network 3300 (e.g., by a processor therein, or acentral server in operable communication therewith) to derive channelstate information (CSI) and feed the CSI back to array 3302 (e.g., areceiver thereof, not separately shown). In at least one embodiment,feedback to array 3302 is performed through backhaul facilities, such asa relay server (described further below with respect to FIG. 34) and/orover Ethernet.

After receiving the CSI feedback, multi-antenna transceiver array 3302may be further configured to implement BF- and NF-encoding based on thereceived CSI. In the case where array 3302 includes a phase arraymulti-antenna system, to realize BF (e.g., for beams 3310), antennaphases φ₁, φ₂, . . . φ_(N) may be determined according to:

arg max_(φ) ₁ _(,φ) ₂ _(. . . φ) _(N) |Σ_(1≤i≤N) h _(i) e ^(jφ) ^(i)|  (Eq. 9)

where N represents the total number of antennas included in array 3302(e.g., of an AP), and h_(i) represents the channel response from anindividual antenna i to the respective UE/mobile subsystem 3312.

Similarly, to realize NF (e.g., for nulls 3306), the antenna phases φ₁,φ₂, . . . φ_(N) may be similarly determined according to:

arg min_(φ) ₁ _(,φ) ₂ _(. . . φ) _(N) |Σ_(1≤i≤N) h _(i) e ^(jφ) ^(i)|  (Eq. 10)

where h_(i) represents the channel response from the individual antennai to the respective satellite subsystem 3308.

FIG. 34 is a schematic illustration of a mobile network 3400implementing satellite system information relay. In an exemplaryembodiment, mobile network 3400 is similar to mobile network 3300, FIG.33, and includes at least one multi-antenna transceiver 3402 generatinga beam pattern 3404, which includes a plurality of nulls 3406respectively formed in directions of a plurality of satellite subsystems3408. In this example, beam pattern 3404 further includes a plurality ofradio beams 3410 respectively formed in directions of a plurality ofmobile subsystems 3412. In the exemplary embodiment, mobile network 3400is in operable communication with a server 3314 (e.g., a central serveror SAS, described above) configured to collect information fromsatellite subsystems 3408 and sensors thereof (e.g., sensor 3314, FIG.33), which may include without limitation the respective locations,frequency channels, angles, antenna gains, site conditions, CSI, etc.

In exemplary operation of multiple network 3400, server 3314 executes acollection operation 3416 of some or all of the information fromrespective satellite subsystems 3408, and then executes a relayoperation 3418 of the collected information to a receiving portion (notseparately shown) of multi-antenna transceiver 3402. In someembodiments, the relayed information may be further relayed (not shownin FIG. 34) from transceiver 3402 to respective mobile subsystems 3412(e.g., UEs including thereof). In at least one embodiment, server 3414is further configured to provide additional information, includingwithout limitation, geographic information and/or building layouts, tomobile network 3400 to further facilitate BF and NF operation.

FIG. 35 is a flow diagram of an exemplary process 3500 for operating amultiple antenna system. In an exemplary embodiment, process 3500 may beimplemented with respect to one or more of the embodiments depicted inFIGS. 23-34. In operation, process 3500 begins at step 3502, in which agrant is received from a server for an AP to transmit (e.g., step 620,FIG. 6). In an exemplary embodiment of step 3502, the grant is receivedafter management by a stoplight system (e.g., FIG. 38, below). In step3504, a multi-antenna receiver receives status information of one ormore satellite subsystems/earth stations adjacent or approximate to therespective AP. Upon completion of step 3504, process 3500 proceeds toexecute one or both of beamforming subprocess 3506 and null formingsubprocess 3508.

Beamforming subprocess 3506 begins at step 3510, in which the multipleantenna system obtains location information for one or more UEsoperating within the range of a cell of the system. In an exemplaryembodiment of step 3510, collection of UE locations is facilitatedutilizing one or more other communication systems belonging to the sameheterogeneous network. Step 3512 is a decision step. In step 3512,process 3500 determines if transmission to/from a particular UE or FWAlocation is “safe,” that is, may be performed without unreasonableinterference from/to a particular FSS site. If, in step 3512, process3500 determines that a particular UE or FA location is not safe, process3500 proceeds to step 3514, in which communication with the particularUE at that location is disabled, and process 3500 then returns to step3510. If, however, in step 3512, process 3500 determines that the UE alocation is safe, process 3500 proceeds to step 3516.

In step 3516, the server and/or the multi-antenna receiver obtains CSIfor at least one UE at location determined to be safe. In step 3518,process 3500 implements beamforming from the multi-antenna transmitterin the direction of the UE for which CSI was obtained in step 3516. Nullforming subprocess includes a step 3520, in which process 3500implements null forming in the direction of the location(s) of one ormore earth stations obtained in the status information received in step3504. The exemplary embodiment described with respect to FIG. 35 isprovided for illustration purposes, and is not intended to be limiting.For example, symmetric and/or similar operations, steps, subprocesses,etc. may be alternatively, or additionally, implemented for UEs in thecase of UEs being equipped with multi-antenna transceivers. In suchinstances, BF and NF may, for example, be jointly processed withmultiplexing mode.

FIG. 36 is a schematic illustration of a multiple antenna system 3600implementing a directional antenna subsystem 3602 for satellite downlinkprotection. In an exemplary embodiment, multiple antenna system 3600represents a wireless communication system, and directional antennasubsystem 3602 includes a plurality of directional antennas 3604 of anAP (also referred to herein as a directional AP) located proximate to anoperational range of an earth station/satellite subsystem 3606. In someembodiments, directional antenna subsystem 3602 is implemented as analternative to a multi-antenna system (e.g., similar to the embodimentsdescribed above). In other embodiments, directional antenna subsystem3602 is implemented in a complementary manner with a multi-antennasystem.

In exemplary operation of system 3600, each directional AP/antenna 3604is configured to provide coverage within a respective coverage area 3608substantially disposed in a direction extending away from earthstation/satellite subsystem 3606. In some embodiments, respectivecoverage areas 3608 may be configured such that collectively, coverageareas 3608 are substantially equivalent to a coverage area provided by aconventional omni-directional AP (not shown in FIG. 36). However,irrespective of similarity of coverage areas, the embodiment illustratedin FIG. 36 realizes substantial benefits over a conventionalomni-directional AP because, unlike in the case of the conventionalomni-directional AP, implementation of directional antenna subsystem3602 advantageously enables system 3600 to minimize interference from/toearth station/satellite subsystem 3606, as described further below withrespect to the comparative examples depicted in FIGS. 37A-B anddescribed with respect to Table 13.

FIG. 37A is a schematic illustration of a mobile network 3700implementing directional coverage implementing directional antenna 3604,FIG. 36, and FIG. 37B is a schematic illustration of a mobile network3702 implementing a conventional omni-directional antenna 3704. In theexemplary embodiment, directional antenna 3604 and omni-directionalantenna 3704 each represent a respective AP (not separately numbered),and may be considered in this example to provide substantially similarcoverage areas (e.g., coverage areas 3608, 3706, respectively) atapproximately the same distance to an earth station (ES) 3708, and withrespect to a relative disposition of a plurality of UEs or FWAtransceivers 3710.

In comparative operation of mobile networks 3700, 3702, the downlinkinterference generated by the respective APs 3604, 3704 may be expectedto be somewhat similar. However, as can be seen from a comparisonbetween FIGS. 37A and 37B, the uplink power levels from the samedistribution of UEs 3710 may be significantly different between the twomobile networks. That is, in the case of omni-directional AP 3704, allof UEs 3710 are contained within coverage area 3706. In contrast, in thecase of directional AP 3604, at least one of UEs 3710 (e.g., UE 3710(3)in this example) is outside of coverage area 3608, and the relativedistribution of UEs 3710 leads to significantly different uplink powerlevels, and therefore also significantly different potential uplinkinterference possibilities, as demonstrated below with respect to Table13.

TABLE 13 UE-ES DIRECTIONAL OMNI-DIRECTIONAL UE LOCATION ANTENNA 3710ANTENNA 3704 3710(1) UE far from Medium uplink power/ Medium uplinkpower/ ES No interference No interference 3710(2) UE close to Low uplinkpower/ High uplink power/ ES No interference Potential interference3710(3) UE on Outside coverage area/ High uplink power/ boresight Nocommunication/ Potential interference of ES No interference

According to the exemplary data provided in Table 13, it can be seen howimplementation of directional antennas according to the embodimentsherein may advantageously substitute for the coverage area of aconventional omni-directional antenna, but while obtaining significantadvantages over such conventional antennas with respect to uplink powerand the avoidance of potential interference of UEs.

Stoplight System for in-band Protection

As described above, the coexistence of mobile or wireless communicationsystems with satellite systems has proven conventionally difficult tomodel with respect to the relatively recent promotion of CBRS in the 3.5GHz band spectrum. Conventional coexistence mechanisms that relyprimarily on only priority tiers, protection zones, and radio sensinghave proven insufficient for the C-band. According to the innovativesystems and methods described herein though, a network of satellitebeacon transmitters and detectors (i.e., BRs) enable the generation of aglobal map (e.g., within an individual country, or around the world) ofpotential radio interference. According to the present systems andmethods, a dynamic interference map may be created in real time usingthe MBP techniques coordinated by one or more central servers.

In an exemplary embodiment of the innovative infrastructures describedherein, individual beacon transmitters may be configured to utilize thesame transmitters used at small cell base stations, therebysignificantly reducing the need for installation of additionalequipment. In other embodiments, the beacon transmitters may beco-located with base stations at the particular FSS sites. Optimally, aplurality of BRs are geographically distributed across a wide area, butneed not to be of uniform architecture, as described above. In somecases, one or more BRs may implement multi-antenna technologies, such asMIMO, to improve the diversity and sensitivity capabilities of therespective receivers. Different BR categories are described below withrespect to FIG. 38.

FIG. 38 is a schematic illustration of a communication system 3800. Inan exemplary embodiment, communication system 3800 is configured tomanage beacon transmission from a beacon transmitter 3802 to one or moreof a variety of beacon detector categories distributed in or among aplurality of FSS sites 3804. The variety of beacon detector categoriesinclude on-site BRs 3806, anchor BRs 3808, and peripheral BRs 3810 eachof which may be configured to directly or indirectly operablycommunicate with one or more servers 3812 (i.e., 1-N servers 3812).According to the exemplary embodiment depicted in FIG. 38, thedistributed network of beacon transmitter(s) 3802, detectors/BRs 3806,3808, 3810, and servers 3812 may be collectively configured (alsoreferred to herein as a “stoplight” system) to operate according to thereal-time and dynamic conditions of system 3800, such that thecapability to detect, measure, and mitigate interference within system3800 is significantly improved for more effective satellite systemprotection, as well as more efficient spectrum use.

In an exemplary embodiment, on-site BRs 3806 include detectors orreceivers that are embedded in, co-located with, and or integral torespective the satellite earth stations 3814 of the FSS sites 3804. Insome embodiments, the various receivers of on-site BRs 3806 areconfigured to form an array at or approximate to a respective earthstation 3814 for a more accurate close-field estimate in particularinstances. As described above with respect to FIG. 15, consideringdeployment of on-site BRs 3806 in approximately all 4700 U.S. FFS sites3804, stoplight system 3800 may be reasonably considered to coverapproximately 98% of the population utilizing only on-site BRs 3806.Nevertheless, it may be desirable to utilize one or more other BRcategories to achieve 100% coverage, and/or in the case where deploymentof on-site BRs 3806 is not, or cannot be, achieved.

Anchor BRs 3808, for example, may include detectors or receiversdeployed near satellite FSS sites 3804 that prohibit or do not implementon-site BRs 3806, and/or to extend the effective beacon coverage rangebeyond 200 dB in hops. Peripheral BRs 3810, on the other hand, functionto supplement the overall beacon infrastructure of stoplight system 3800through the deployment of additional, peripheral detectors/receivers atnon-site facilities, such as cable strands, for example. In someinstances, this deployment of peripheral BRs 3810 advantageouslyfunctions according to principles similar to those of environmentalsensing capability (ESC) for radar systems.

In exemplary operation of stoplight system 3800, a local server (e.g.,server 3812(1)) is configured to collect information from one or more ofthe distributed BRs 3806, 3808, 3810, and provides the local viewobtained thereby to a global server (e.g., server 3812(2) in thisexample). Alternatively, a plurality of servers 3812 are configured tointerchange their respective data such that each so-configured server3812 is enabled to build its own global interference map. In theexemplary embodiment, each such generated global interference map shouldbe substantially identical to the global interference maps generated atother servers 3812. In at least one embodiment of stoplight system 3800,N is a substantially large number such that many server providers 3812are integrated among system 3800 to more reliably prevent fragmentationor gaps of coverage.

In an exemplary embodiment, system 3800 utilizes information provided toservers 3812 to dynamically generate and/or regenerate a radio map ofpotential interference over the entire area covered by system 3800.Stoplight system 3800 is therefore further advantageously enabled toestablish still further protection mechanisms, including withoutlimitation, channel selective transmission, power restriction, andzoning, based on the mapping information generated/regenerated byservers 3812.

Interference Detection in Shared Spectrum Channels

A number of systems and methods for protecting satellite receivers frominterference from adjacent mobile cells are described above. Several ofthe embodiments herein implement beacons and/or a specialized beaconinfrastructure to measure the potential interference between a mobilecell and the satellite receiver.

The following embodiments further describe innovative systems andmethods that utilize the LTE signal itself for the satellite receiver todetect interference, and thereby avoid the need for dedicated beacontransmitters at the mobile cells/cellular devices. The presentembodiments therefore further achieve significant cost reduction byenabling the use of an expensive and readily available hardware todetect and/or measure the LTE signal at the satellite receiver. Moreparticularly, the following embodiments advantageously detect thepresence of nearby mobile cells that can potentially interfere with areceiver in a nearby area, and enable control of local node operationaccording to the detected presence.

FIG. 39 illustrates an exemplary interference detection system 3900.System 3900 includes a cell tower 3902 broadcasting to one or moremobile cellular devices (e.g., UEs) 3904 operating within a vicinity ofa satellite receiver 3906. In the exemplary embodiment depicted in FIG.39, satellite receiver 3906 is equipped with at least one beacondetector 3908. Both of satellite receiver 3906 and beacon detector 3908may be in operable communication with a system operator 3910 in a mannersimilar to the embodiments described above. In this example, cell tower3902 and cellular devices 3904 are configured to transmit and receiveLTE signals 3912.

An LTE signal (e.g., LTE signal 3912) may include many associatedcomponents. One such component is the PSS (Primary SynchronizationSignal) which is fundamental to LTE signals 3912, and is used bycellular devices 3904 to detect the presence of and identify a mobilecell or mobile cell tower 3902, and then to synchronize the particularcellular mobile device 3904 with cell tower 3902. The PSS may, forexample, be sent periodically once every 5 ms, for a duration of 71 μs.

As described above, the PSS is based on a frequency-domain Zadoff-Chu(ZC) sequence, which is itself a construction of Frank-Zadoff sequences.ZC codes have a useful property of having zero cyclic autocorrelation atall nonzero lags. When used as a synchronization code, the correlationbetween the ideal sequence and a received sequence is greatest when thelag is zero. When there is any lag between the two sequences, thecorrelation is zero. Utilization of the ZC-based PSS for interferencedetection is described further below with respect to FIGS. 40-42.

FIG. 40 is a schematic illustration of a signal frame architecture 4000.In an exemplary embodiment, frame architecture 4000 represents an LTEsignal and includes a plurality of subframes 4002, and a correspondingplurality of timing slots 4004. In this example, architecture 4000 isdepicted to include two timing slots 4004 for each subframe 4002. Eachtiming slot 4004 includes a plurality of symbols 4006 (six symbols 4006for each timing slot 4004, in this example), and at least one PSS 4008.In the exemplary embodiment depicted in FIG. 40, PSS 4008 is repeatedonce every six symbols 4006, that is, one per timing slot 4004.Accordingly, interference detection may be reliably performed bydetecting the presence of PSS 4008 within architecture 4000.

More particularly, the detection of PSS 4008 is enabled through use ofan autocorrelation function (e.g., a ZC sequence) between a referencesequence stored at the receiver (e.g., satellite receiver 3906, FIG.39), on the one hand, and the signal seen at the receiver, on the otherhand. Since the PSS is expected to be sent from the cell on a periodicbasis, the autocorrelation between the reference sequence and the signalmay be performed repeatedly over time, and the various received signalsand results of the autocorrelation results may be dynamicallyaccumulated over time for increasing accuracy during operation.According to the present embodiments, as the number of autocorrelationiterations increase, the PSS may increasingly be detected at lower andlower SNR values. For example, if the SNR is 0 dB, then the number ofiterations may be 6, whereas, if the number of iterations are increasedto 15, then PSS 4008 may be detected at an SNR value as low as −12 dB.The person of ordinary skill in the art will understand that theseexemplary numerical values are provided solely for purposes ofillustration, and not in a limiting manner.

FIG. 41 is a schematic illustration of a signal frame architecture 4100.Architecture 4100 is similar to architecture 4000, FIG. 40, in severalrespects, and includes a plurality of subframes 4102, a correspondingplurality of timing slots 4104 (e.g., two timing slots 4104 for eachsubframe 4102, in this example), and a plurality of symbols 4106 foreach timing slot 4104 (six symbols 4106 for each timing slot 4104, inthis example as well). Different from architecture 4000 though,architecture 4100 groups into timing slot pairs 4108 adjacent timingslots 4104 that bridge the architectural boundary between adjacentsubframes 4102. Similar to architecture 4000, architecture 4100 alsorepresents an LTE signal.

As can be seen from the exemplary embodiment depicted in FIG. 41, eachtiming slot pair 4108 includes only a single PSS 4110, as opposed to aPSS for each timing slot 4106. Nevertheless, in this example, eachtiming slot pair 4108 further includes at least one SecondarySynchronization Signal (SSS) per pair. Accordingly, interferencedetection may also be reliably performed using different LTE signalarchitectures.

FIG. 42 is a flow diagram for an exemplary interference detectionprocess 4200. In an exemplary embodiment, interference detection process4200 is executed by a processor (not shown) of a central server or SAS(e.g., operator 3910, FIG. 39) in some embodiments, process 4200 isexecuted by a processor disposed at, or in operable communication with,one or both of satellite receiver 3906 and an eNodeB (not shown)stationed at tower 3902. Process 4200 may be executed with respect tothe simplified system 3900 depicted in FIG. 39, or may represent asubprocess of the more complex MBP schemes described above, to enableinterference detection at the satellite receiver.

Process 4200 begins at step 4902, in which the eNodeB of the system isstarted up (e.g., powered on, becomes active after an idle period,etc.). At step 4204, process executes a Hold State, in which the eNodeBsends a PSS at a nominal operational power level. In an exemplaryembodiment of step 4204, no other data (either uplink or downlink) issent by the eNodeB during the Hold State. In some embodiments of step4204, the eNodeB informs the central server/SAS (or a system processorconfigured to coordinate spectrum sharing) of entry into the Hold State,and the eNodeB maintains the Hold State this mode for a predeterminednumber (k) of minutes.

At step 4206, the PSS receiver (e.g., satellite receiver 3906, beacondetector 3908, etc.) is configured to continuously capture signalsacross the various bands of interest and perform autocorrelation toenable PSS detection. In an exemplary embodiment of step 4206, a PSSdetection algorithm at the receiver may be limited to N iterations,where N is defined according to a value (predetermined or dynamicallyobtained through MBP) for maximum allowable interference.

Step 4208 is a decision step. In step 4208, process 4200 determines ifthe PSS is detected based on the results of step 4206. If the PSSreceiver detects a presence of the PSS, then process 4200 proceeds tostep 4210, in which the PSS receiver reports the detected measurements(e.g., PSS SNR detection level, mobile cell ID, etc.) to the centralserver/SAS. In step 4212, based on the report from the PSS receiver instep 4210, the central server transmits operational instructions to theeNodeB. In an exemplary embodiment of step 4212, the operationalinstructions include instructions for the eNodeB to (i) fully operate,(ii) operate at a lower power, or (iii) cease operation (e.g., completedenial).

Returning back to step 4208, if no PSS was detected from step 4206,process 4200 proceeds to step 4214, in which the eNodeB maintains theHold State (e.g., from step 4204) for k minutes. If, after k minutes ofthe eNodeB reporting the Hold State to the central server, andoptionally, if the central server receives no reports of a detected PSSfrom a PSS receiver, process 4200 determines that no PSS is present,that is, that a PSS is not observed by any receiver reporting to thecentral server (e.g., within the vicinity of satellite receiver). Uponthis determination, the central server may calculate that the eNodeBwill not interfere with the satellite receiver.

The systems and methods described above thus provide an alternative, orsupplemental, technique for detecting potential interference from anearby LTE signal (e.g., from a UE) to a satellite receiver. Theseinnovative interference detection techniques though, by utilizinginformation that is already present in the LTE signals themselves,require no substantive changes to the hardware or software at theeNodeB. Additionally, the present embodiments efficiently utilizeexisting resources that are already available in commercial PSSdetectors, which are used in essentially LTE mobile handsets (billionsof such handsets being actively deployed throughout the world atpresent).

The present systems and methods thus realize a significantly moreaccurate measurement of the PSS and its characteristics based onreliable digital signal processing techniques. Moreover, the presentPSS-based interference detection scheme advantageously provides thecentral server/SAS specific information (e.g., cell ID, etc.) toidentify the mobile cell, but without the need to send additionalinformation from the mobile cell, which would create additional signaltraffic.

Exemplary embodiments of spectrum sharing management and interferencedetection systems and methods are described above in detail, and moreparticularly, embodiments relating to beacon detection systemconfiguration and operation. The systems and methods of this disclosurethough, are not limited to only the specific embodiments describedherein, but rather, the components and/or steps of their implementationmay be utilized independently and separately from other componentsand/or steps described herein.

Although specific features of various embodiments of the disclosure maybe shown in some drawings and not in others, this convention is forconvenience purposes and ease of description only. In accordance withthe principles of the disclosure, a particular feature shown in adrawing may be referenced and/or claimed in combination with features ofthe other drawings.

Some embodiments involve the use of one or more electronic or computingdevices. Such devices typically include a processor or controller, suchas a general purpose central processing unit (CPU), a graphicsprocessing unit (GPU), a microcontroller, a reduced instruction setcomputer (RISC) processor, an application specific integrated circuit(ASIC), a programmable logic circuit (PLC), a field programmable gatearray (FPGA), a digital signal processing (DSP) device, and/or any othercircuit or processor capable of executing the functions describedherein. The processes described herein may be encoded as executableinstructions embodied in a computer readable medium, including, withoutlimitation, a storage device and/or a memory device. Such instructions,when executed by a processor, cause the processor to perform at least aportion of the methods described herein. The above examples areexemplary only, and thus are not intended to limit in any way thedefinition and/or meaning of the term “processor.”

This written description uses examples to disclose the embodiments,including the best mode, and also to enable any person skilled in theart to practice the embodiments, including making and using any devicesor systems and performing any incorporated methods. The patentable scopeof the disclosure is defined by the claims, and may include otherexamples that occur to those skilled in the art. Such other examples areintended to be within the scope of the claims if they have structuralelements that do not differ from the literal language of the claims, orif they include equivalent structural elements with insubstantialdifferences from the literal language of the claims.

We claim:
 1. A communication system, comprising: a satellite receiver inoperable communication with a central server; a cellular node configuredto operate within a proximity of the satellite receiver; and at leastone mobile communication device configured to communicate (i) with thecellular node, (ii) within the proximity of the satellite receiver, and(iii) using a transmission signal capable of causing interference to thesatellite receiver, wherein the satellite receiver is configured todetect a repeating portion of the transmission signal and determine apotential for interference from the at least one mobile communicationdevice based on the detected repeating portion.
 2. The communicationsystem of claim 1, wherein the at least one mobile communication deviceis an LTE device and the transmission signal is a long term evolution(LTE) signal.
 3. The communication system of claim 2, further comprisinga beacon detector (i) in operable communication with at least one of thecentral server and the satellite receiver, and (ii) configured tomeasure the repeating portion of the LTE signal.
 4. The communicationsystem of claim 2, wherein the LTE signal comprises a plurality ofbroadcast frames.
 5. The communication system of claim 4, wherein eachframe of the plurality of broadcast frames comprises a plurality ofsubframes and a plurality of timing slots.
 6. The communication systemof claim 5, wherein each timing slot of the plurality of timing slotsincludes a plurality of symbols.
 7. The communication system of claim 6,wherein each frame comprises two timing slots for each subframe.
 8. Thecommunication system of claim 6, wherein each timing slot includes oneprimary synchronization signal (PSS) in one symbol of the plurality ofsymbols.
 9. The communication system of claim 8, wherein the repeatingportion of the LTE signal is the PSS.
 10. The communication system ofclaim 6, wherein every other timing slot includes one PSS in one symbolof the plurality of symbols.
 11. The communication system of claim 10,wherein each alternating timing slot located between the every othertiming slots includes one secondary synchronization signal (SSS) in onesymbol of the plurality of symbols.
 12. The communication system ofclaim 1, wherein the central server comprises a spectrum access system.13. The communication system of claim 1, wherein the at least one mobilecommunications device is a user equipment device.
 14. The communicationsystem of claim 1, wherein the cellular node is an eNodeB of a cellulartower.
 15. A method of detecting interference to a satellite receiverfrom a mobile communications device in communication with a cellularnode in proximity to the satellite receiver, comprising the steps of:powering the cellular node; causing the cellular node to broadcast aprimary synchronization signal (PSS) at a nominal power level; capturingthe broadcast PSS; determining, from the captured PSS, an operation ofthe cellular node; and instructing the cellular node, based on thedetermined operation, to (i) operate at full power, (ii) operate at alower power, or (iii) cease operation.
 16. The method of claim 15,wherein the cellular node is an eNodeB of a cellular tower.
 17. Themethod of claim 15, wherein the cellular node and the mobilecommunications device operate according to a long term evolution (LTE)protocol.
 18. The method of claim 15, wherein the step of causingfurther comprises a substep of preventing the cellular node fromtransmitting data other than the PSS for a predetermined amount of time.19. The method of claim 15, wherein the step of capturing iscontinuously repeated for a predetermined number of iterations.
 20. Themethod of claim 15, wherein the predetermined number of iterations isbased on a value of a PSS detection algorithm executed by a processor ofa central server in operable communication with the satellite receiver.